Of the several hundred landscape painters of the Dutch Golden Age, the best-known and most influential is Jacob van Ruisdael, whose paintings were described by Vincent van Gogh as “sublime”. Van Ruisdael was starting his career just as Nicolas Poussin was reaching his zenith in Rome, and the two were major influences on all subsequent landscape artists, particularly Thomas Gainsborough, John Constable and JMW Turner.

Jacob Isaackszoon van Ruisdael (1628/9-1682) was born in Haarlem into a family of painters. Presumably apprenticed within the family workshop, he was admitted to the local Guild of Saint Luke in 1648, and from the outset appears to have specialised in landscape painting.

Van Ruisdael’s earliest landscapes contained trees, as they would at a time when trees and woods were more extensive in their coverage across the whole of Europe. The view in Landscape with a Church (c 1645) looks familiar, as its composition was used by Gainsborough, Constable, and many other later artists. Prominent at the left, and forming repoussoir, is the hulk of an old tree, younger branches sprouting from the remains, a recurrent theme in Gainsborough as well as van Ruisdael. A recession in depth on the right leads to the brighter-lit church in the middle distance.

The trees here are painstakingly constructed from the anatomy of their branches, with leaves painted individually in the foreground, but delicately en masse in the further distance. Bark colour, texture, and rich lichen growth are also shown in fine detail.

Van Ruisdael soon showed a deep understanding of the stages in the life and looks of oak trees. In Road through an Oak Forest (c 1646-7) he captures the later life of a stag-headed oak, that long ago lost its crown, on the left, a flush of new growth on a fallen trunk, and another still clinging onto life despite a great split at its base.

Judging from the girth of their trunks, the oak trees shown here are around 400 years old, making it likely that they were saplings in the thirteenth century, possibly even earlier. They form a remarkable window back in time to the late Middle Ages.

Some of van Ruisdael’s sketches and drawings have also survived, among them Landscape with a Stone Bridge (c 1647). This shows his development of foliage from branch structure quite clearly, and the fact that he didn’t block in that foliage, preferring gestural squiggles and other marks.

Van Ruisdael was a faithful observer of the different species of tree and their forms, as shown in his timeless A Wooded Landscape with a Pond from about 1648. He has maintained careful, anatomical construction even in the prominent tree at the centre right, in the middle distance, and the canopies appear light and leafy.

Gentle rural decay is shown not only in the ruined buildings in Landscape with a Mill-run and Ruins (c 1653), but also in the stag-head tree in the centre of the painting.

He moved to Amsterdam in 1657, to take advantage of its growing prosperity. He appears to have travelled little, remaining within the European lowlands and venturing only just over the border into Germany. His only known student was Meindert Hobbema, who became an accomplished landscape painter who also depicted trees as important elements within his works.

Probably painted soon after he had moved to Amsterdam, The Great Forest (c 1655-60) shows travellers along a track passing at the edge of an ancient woodland, with an assortment of trees in various states of advancing age, including some reduced to stag-heads.

The upland landscape shown in The Forest Stream (c 1660) was clearly not one that van Ruisdael had ever seen, but must have been composed from studying the paintings of others, and talking to those more widely travelled. His trees remain much as before, with a gnarled and twisted stag-head at the right, and at the left a near-dead trunk poised in slow-motion collapse into the stream.

Although most of van Ruisdael’s paintings are in full daylight, as with his contemporaries he also explored more transient light effects, in A Marsh in a Forest at Dusk (c 1660). Now the ancient trees launching themselves out from the bank at the right have engaged with those growing in the marsh. The effect of the late dusk light on their canopies is spectacular, as are the thin banks of cloud above, lit by the setting sun. His careful leaf-by-leaf depiction of canopies of different tree species generates distinct and life-like textures.

In Landscape with Waterfall (c 1660-70), van Ruisdael revisited the distant church framed by nearer trees theme of Landscape with a Church above. Perhaps this time the church is a little too far away, though still an inspiration to Constable and Gainsborough. At the right a birch collapses off the edge, and there is a pair of ancient wizened oaks filling the centre.

He continued to develop the theme of old oaks and water in Oaks at a Lake with Water Lilies in about 1665. Again a dying ancient hulk stands like a prow from the bank at the left, and he shows bright flowers on the water-lilies.

Many of his woods are either unpopulated, or the few people providing staffage are barely visible against their surroundings. His undated A Road through an Oak Wood is different, with a couple of travellers on its road, and woodland activities of clearing and burning at the left.

The Golden Age was primarily based on prosperity from trade, not home production, but increasing demand from the affluent cities led to greater timber production, particularly for ships and buildings, and the clearing of woods to augment farmland.

My final selection is perhaps his most detailed essay on the effects of advanced age on trees, Three Great Trees in a Mountainous Landscape with a River (c 1665-70). Although the mountains are borrowed or imaginary, the three trees of the title seem almost impossibly intertwined. The nearest is struggling to survive, remains of its former glory resting, limbs in the air, at its foot.

When the Dutch economy collapsed in 1672, he appears to have remained relatively prosperous, and continued to work in Amsterdam until his death a decade later, in 1682.

References

Wikipedia
Slive, S (2005) Jacob van Ruisdael: Master of Landscape, Royal Academy of Arts, London. ISBN 978 1 903973 24 0.
Ashton, PS, Davies, AI & Slive, S (1982). “Jacob van Ruisdael’s trees”. Arnoldia 42 (1): 2–31; available from JSTOR.

Last week I drew attention to problems interpreting the timestamps of files in macOS, generating lively discussion with Chris and Richard. Although the gist of that article stands, it was clear that there remained several issues, and this sequel tries to address those better, with the aid of a new app, Dropera 2. The TL;DR for this article is that timestamps are even more complicated than I previously described.

The first task was to develop a tool for reading and recording these timestamps reproducibly. Although the four key timestamps are exposed in Precize, opening a file in that app is likely to change at least one of them. For a substitute I turned to an earlier SwiftUI demo, Dropera, with its drag-and-drop support to handle file URLs without opening, reading or otherwise changing the file.

Timestamps

This new version of Dropera had then to read the right timestamps and convert them into accessible dates and times. For some timestamps, we’re spoiled for choice: time of creation of a file, shown in the Finder as Date Created, is saved in an APFS file’s attributes as create_time, exposed in the stat command as st_birthtime, and accessible within an app’s code as the NSFileCreationDate file attribute or creationDate URL resource. To establish which timestamp is which, I have compiled a table giving the sources I have been able to discover.

For Dropera, following careful comparison with the values delivered in stat, I selected:

• Creation from NSFileCreationDate
• Modification from NSFileModificationDate
• Attribute modification from attributeModificationDate
• Access from contentAccessDate.

The last two aren’t available in the Finder or elsewhere in the GUI, while the Finder does provide Date Last Opened, Date Added and Content Created:

• Date Last Opened isn’t related to Access Time, but is recorded in the com.apple.useddate extended attribute. Unfortunately, adding and manipulating that may change the Attribute Modification timestamp, so has to be avoided. As Apple doesn’t appear to document the xattr or its interpretation, I have avoided looking at it any further here.
• Date Added is the timestamp when a file was added to its current directory. As that isn’t strictly speaking a file attribute, I will ignore it here.
• Embedded records of Content Created require file data to be read, so accessing them is likely to update at least one of the key timestamps.

Each of those three is available from the metadata indexed by Spotlight, but that’s an indirect and unreliable way to access them.

Using Dropera

To use Dropera to read the four key timestamps just drop the file onto its window, and the app will then display the filename, its path, and the four timestamps in the order of Creation, Modification, Attribute modification and Access times.

Adjust the window width to make these most convenient to read. The layout shown above is compact and automatically splits each timestamp into date and time components. In other uses, you might prefer to widen the window so each entry takes a single line.

To refresh the values shown for the current files, click on the Refresh tool. Although the window continues to display just the single set of entries, the previous timestamps are saved in memory, and the whole history since the last drag-and-drop onto that window can be exported to a text file using the Save as text tool. You can also select the line of results, copy and paste that into another app if you prefer.

Drop multiple files onto Dropera’s window and all their timestamps will be shown. You can then select continuously (Shift-click) or discontinuously (Command-click) to copy those values, and Refresh them.

Demonstration

Open TextEdit, create a new file and set its type to plain text. Add a few words and save it somewhere convenient. Then open Dropera, and drop that file onto its window to inspect its timestamps. They’re likely to show Creation and Modification times the same, Attribute modification slightly later, and Access another second or so afterwards.

Next make a small change to that document and save it. Click Dropera’s Refresh tool and only the Creation time remains unchanged. Close that document in TextEdit, and Refresh the times again to confirm that none have changed. Now select the file in the Finder so its QuickLook thumbnail is previewed. When you Refresh its times, you should see its Access time has been updated. Now double-click the file to open it in TextEdit, and check times again while the file is still open. Attribute modification and Access times are altered, but remain the same after you have closed the document. Export those records as a text file, and you should see:

• Creation time remains unchanged throughout.
• Modification time changes once, when the second version was saved.
• Attribute modification time changes twice, when the modified file was saved, and when the file was reopened.
• Access time changes three times, the additional occasion being when you viewed the document’s thumbnail in the Finder.

Dropera 2, which requires macOS 14.6 or later, is available from here: dropera20

Enjoy!

Since ancient times people have written, drawn and painted using pigments and dyes in water, often without any binder to adhere them to the ground. These are generically termed inks, and distinct from other media such as watercolours or the temperas. Most common among them is India ink, whose essential ingredients are carbon particles from soot, suspended in water. When applied to a suitably absorbent ground that has stood the test of centuries.

Hieronymus Bosch’s study of The Owl’s Nest from around 1505-1516 is a good example of a pen and ink drawing starting to transcend into painting.

Washes applied using a brush became common in sketches made in front of the motif, such as Egbert van der Poel’s Fire in the Nieuwe Kerk, Amsterdam, in 1645. Known for his paintings of fires, he used these sketches to paint his famous brandjes in the studio. Landscape artists such as Nicolas Poussin and Claude Lorrain used the same sketching media working en plein air to build image libraries for the idealised landscapes used in their finished paintings.

By the early nineteenth century, artists like Samuel Palmer were creating works that are to all intents and purposes full-blown paintings using black and coloured inks, such as this atmospheric nocturne of Cornfield and Church by Moonlight from about 1830.

Used without a binder, inks normally rewet and smudge or blur, so have to be applied after any watercolour. Adding a binder such as shellac to India ink makes it waterproof when it has dried, and this was used in combination with watercolours by illustrators and painters such as the great Arthur Rackham, here in one of his illustrations for an edition of Charles Dickens’ A Christmas Carol.

A related medium that also crossed over from drawings and illustrations into paintings is casein, a protein-based tempera. It too has a long history, but didn’t become popular among artists until the late nineteenth century. Casein is a protein originally obtained from sour milk, but by the nineteenth century it was more usually prepared by the addition of rennet, enzymes used in cheese manufacture, extracted from the stomachs of calves.

Casein powder is then turned into paint by dispersion in an alkaline solution, typically made from lime or borax, and pigment is ground in. When lime is used the paint works best on porous grounds, but must be used fresh. When a little linseed oil is added to borax casein, a shelf-life of several months or more is possible. Casein paints dry as quickly as egg tempera, but can be reworked for a period until their binder has fully hardened. Once that has taken place, their paint film is robust and stable.

The earliest painting I have seen that is known to have been made using casein paints is William Morris Hunt’s unusual view of Niagara from 1879. Hunt deviated here from his customary use of oils, although he still applied his paint to a prepared canvas support.

One of the most famous artists to have used casein paint is Gustav Klimt. In 1902, he used it in a frieze of 24 metres (nearly 80 feet) length for the fourteenth exhibition of the Vienna Secession, his Beethoven Frieze, of which that above is a section known as The Hostile Powers, and that below is Nagging Grief. He applied his casein paint directly onto mortar with added stucco, gold leaf, and other materials. This is known to be a robust form of wall-painting that is much more accommodating than fresco, and just as enduring, but has never become popular.

A few of Colin Campbell Cooper’s skyscraper cityscapes were painted using casein media, including this view of Flatiron Building, Manhattan from about 1908. He was equally proficient in watercolour and oils, and I don’t know why he experimented with casein, nor why he used it so infrequently.

Another Vienna-based artist, Albin Egger-Lienz, also used casein on occasion, here in this fourth of several different versions of Totentanz (Dance of Death) from 1915.

During the twentieth century, casein paints didn’t become popular but continued in use, particularly by those who also made illustrations. Just when they were attracting a following among artists such as Andy Warhol, they were rapidly displaced by acrylics. Despite that, casein paint is still available today, sold by Pelikan under the brand name of Plaka.

Apple silicon chips are designed to minimise the power and energy they use without compromising their performance. One of the many tricks they use is to run the cores in their CPUs at variable frequencies, and in more recent models to shut down those cores they don’t need. At the start of the year, thanks to the many who contributed information about their Macs, we were able to assemble a table of CPU core frequencies for all the M-series chips then available. Those demonstrated that frequencies differed between families such as M1 and M2, and between models within each family such as M2 Pro and Max, as well as between P and E cores.

Since then Apple has released two new chips, the M3 Ultra available in the current Mac Studio, and most recently the base M5 that has recently been impressing so many. This article briefly reviews what we know about CPU core frequencies, and appeals for information about those two new chips.

The best way to discover which frequencies are supported by the P and E cores in the CPU of an Apple silicon chip is using the output of the command tool powermetrics. This lists frequencies for P and E cores, and this article assumes that those it gives are correct. Although it’s most likely that these frequencies aren’t baked into silicon, so could be changed, I’ve seen no evidence to suggest that Apple has done that in any release Mac.

Frequencies

If powermetrics is to be believed, then the maximum frequencies of each of the CPU cores used in each generation differ from some of those you’ll see quoted elsewhere. Correct values should be:

• M1 E 2064 MHz or 2.1 GHz; P 3228 MHz or 3.2 GHz;
• M2 E 2424 MHz or 2.4 GHz; P 3696 MHz or 3.7 GHz;
• M3 E 2748 MHz or 2.7 GHz; P 4056 MHz or 4.1 GHz;
• M4 E 2892 MHz or 2.9 GHz; P 4512 MHz or 4.5 GHz.

However, not all variants within a family can use those maximum frequencies. The full table of frequencies reported by powermetrics is:

This is available for download as a Numbers spreadsheet and in CSV format here: mxfreqs

Why those frequencies?

Depending on workload, thread Quality of Service, power mode, and thermal status, macOS sets the frequency for each cluster of CPU cores. Those used range between the minimum or idle, and the maximum, usually given as the core’s ‘clock speed’ and an indication of its maximum potential performance. In between those are as many as 17 intermediate frequencies giving cores great flexibility in performance, power and energy use. Core design and development uses sophisticated models to select idle and maximum frequencies, and evidently to determine those in between.

Looking at the table, it would be easy to assume those numbers are chosen arbitrarily, but when expressed appropriately there are patterns. Apple’s engineers have clearly put considerable effort into picking optimised frequencies for each of the families and variants within them. If you think this is fine detail and only the maximum frequencies count, then bear in mind that both P and E cores spend a lot of their time running at those intermediate frequencies.

How to report frequencies

If you have a Mac Studio M3 Ultra or MacBook Pro M5 you can add to this collection, please open Terminal and run the command
sudo powermetrics -n 1 -s cpu_power
which then prompts you for your admin password. A few seconds later the window will fill with a single set of measurements looking like this:

All I’d like is a copy containing 3 lines from that:

• Machine model at the top, to tell me which Mac it is, thus which chip.
• E-Cluster HW active residency, which contains a list of frequencies for the E cores.
• P-Cluster HW active residency, which contains a longer list of frequencies for the P cores.

To help, I have highlighted those three lines in the screenshot above.

Thank you.

After meeting some political traitors, Dante and Virgil have come across Count Ugolino, who is gnawing the back of the head of Archbishop Ruggieri as a dog chews a bone. Their story is one of the most famous and horrific in the whole of the Divine Comedy.

Ugolino raises his mouth from the cleric’s head and wipes his lips on his victim’s hair. He then introduces himself and the Archbishop. He explains how he, a leading politician at the time, was imprisoned with his young sons and left to starve to death. In his hunger he tried gnawing his own hands, but his sons suggested that their father should eat them instead.

This glue tempera painting by William Blake is one of the few that isn’t taken from his last works illustrating the Divine Comedy, but is a prior work. Unfortunately, its equivalent in Blake’s last series got no further than a pencil sketch before the artist’s death.

Ugolino stopped gnawing his own flesh, and sat in silence day after day, watching his sons die in front of him. By the time the last was dead, the Count himself had gone blind. Once confident there was no life left in their bodies, his hunger overcame his grief.

In history, Ugolino was born into a Ghibelline family in the city of Pisa. He soon changed allegiance to the Guelphs, whom he helped in their quest for power in Pisa. When that was unsuccessful, the Count was imprisoned and exiled, but later led Pisan naval forces against its rival Genoa, for which he was made Pisa’s leader.

In an act of political expediency, Ugolino then handed over Pisan castles to Lucca and Florence, following which he conspired with Ghibellines including Archbishop Ruggieri. This backfired on him, and the Archibishop had him imprisoned with his two sons, two grandsons, and another young man. After eight months there, the door was locked and nailed shut, and its key thrown into the river. Ugolino and the five young men died fairly quickly of starvation.

As far as I’m aware, this painting of Count Ugolino and his Children in the Dungeon is the only work by Joshua Reynolds taken from Dante’s Divine Comedy. Exhibited at the Royal Academy in 1773, nearly five hundred years after the death of the Count, I’m not aware that Reynolds had access to any contemporary images of his subject.

It’s therefore revealing that this slightly later copy was one of many images of the faces of the famous and infamous on which Lavater based his textbook of physiognomy, which in turn was popular among painters, making it a self-fulfilling fantasy.

Dante and Virgil move on from Ugolino’s tragedy to meet more traitors frozen into Lake Cocytus in Hell, as they make their way towards the bottom of its pit, and Lucifer himself.

The artists

William Blake (1757–1827) was a British visionary painter and illustrator whose last and incomplete work was an illustrated edition of the Divine Comedy for the painter John Linnell. Most of his works shown in this series were created for that, although he did draw and paint scenes during his earlier career. I have a major series on his work here.

Pierino da Vinci (1530–1553) was an Italian Renaissance sculptor, the son of Leonardo da Vinci’s younger brother. He died of malaria, which was still endemic in much of Europe at that time, at the age of only 23, leaving few examples of his work.

Gustave Doré (1832–1883) was the leading French illustrator of the nineteenth century, whose paintings are still relatively unknown. Early in his career, he produced a complete set of seventy illustrations for translations of the Inferno, first published in 1857 and still being used. These were followed in 1867 by more illustrations for Purgatorio and Paradiso. This article looks at his paintings.

Joseph Anton Koch (1768-1839) was an Austrian landscape painter, who worked mainly in Neoclassical style. During his second stay in Rome, he was commissioned to paint frescos in the Villa Massimi on the walls of the Dante Room there, which remain one of the most florid visual accounts of Dante’s Inferno. He completed those between 1824-29. He also appears to have drawn a set of illustrations for Dante’s Inferno in about 1808.

Johann Caspar Lavater (1741-1801) was a Swiss poet and philosopher who was a friend of the painter Henry Fuseli. Between 1775-78, he published an early textbook on physiognomy, in which he related physical appearance, particularly of the face, to specific character traits of individuals. He did this using many illustrations of famous and infamous people. This attracted a popular following, including many artists.

Sir Joshua Reynolds (1723–1792) was the major portrait painter of his day, one of the co-founders and first president of the Royal Academy of Arts in London. He enjoyed royal patronage, and moved in the highest of artistic circles. However, his work and teaching were lambasted by William Blake, and some of his paintings have suffered serious problems in their paint layer as a result of his experimentation with pigments and technique.

Jan van der Straet, also commonly known by his Italianised name of Giovanni Stradano (1523-1605), was a painter who started his career in Bruges and Antwerp in Belgium, but moved to Florence in 1550, where he worked for the remainder of his life. Mannerist in style, he worked with printmakers in Antwerp to produce collections of prints, including an extensive set for The Divine Comedy.

References

Wikipedia
Danteworlds

Robin Kirkpatrick (trans) (2012) Dante, The Divine Comedy, Inferno, Purgatorio, Paradiso, Penguin Classics. ISBN 978 0 141 19749 4.
Richard Lansing (ed) (2000) The Dante Encyclopedia, Routledge. ISBN 978 0 415 87611 7.
Guy P Raffa (2009) The Complete Danteworlds, A Reader’s Guide to the Divine Comedy, Chicago UP. ISBN 978 0 2267 0270 4.
Prue Shaw (2014) Reading Dante, From Here to Eternity, Liveright. ISBN 978 1 63149 006 4.

I hope that you enjoyed Saturday’s Mac Riddles, episode 331. Here are my solutions to them.

1: A red Canadian named by Jef and after John came in 1984.

2: A wonder for cooking led by Larry came in 1993.

3: This fruit from Newtown flopped between 1996-97.

The common factor

I look forward to your putting alternative cases.

For much of the last 25 years, macOS has had ill-defined and pervasive problems that have often been attributed to incorrect permissions in various parts of the file system. As a result, one of the common panaceas has been to repair those permissions, using procedures that have changed over those years.

Repair disk permissions

Until the introduction of System Integrity Protection (SIP) in 10.11 El Capitan, these problems generally resulted from files within the system acquiring incorrect permissions. To address this, Disk Utility had a feature to check and repair permissions of all major parts of the system, based on information contained in BoM files for system updates and installations. Repairing permissions in this way became one of the main panaceas in those older versions.

Although primarily intended to deliver better security protection, one of the benefits of SIP was that it largely prevented system files from gaining incorrect permissions, and the feature to repair them was removed from Disk Utility. In any case, because of SIP it was no longer possible for Disk Utility to change the permissions of files that were protected by SIP.

Reset user permissions

When macOS 10.12 Sierra was released, a different problem appeared, in which permissions were apparently set incorrectly not in system files generally, but in the user’s Home folder, specifically in ~/Library/Preferences. To address this Apple added a new verb to the already complex command tool diskutil, resetUserPermissions, and described how to use this in a support note. It’s perhaps no coincidence that this new problem appeared at about the same time that the cfprefsd service took on management of those preference files, and just one year after repairing disk permissions ceased.

At that time, the following problems were attributed by Apple to incorrect permissions in ~/Library/Preferences:

• changes to preference settings, particularly those for System Preferences, do not ‘stick’;
• changes made to the Dock do not ‘stick’;
• you are asked to authenticate when trying to move or alter some folders in your Home folder;
• when trying to save, you are told that the file is locked, or that you don’t have permission;
• Preview, TextEdit, and App Store apps (which are sandboxed) may crash when opened;
• alerts appear warning that the startup disk has no more space available for app memory;
• Safari or SafariDAVClient use large amounts of resources (memory);
• the Mac runs very slowly;
• iTunes cannot sync a device;
• there are problems with Photos or iPhoto libraries, including inability to import into the library, or forgetting the library each time the app is opened.

Most if not all of those could have been attributable to problems resulting from bugs in cfprefsd.

Repair Home permissions

Five years ago, Apple changed its recommendations to include running a new tool repairHomePermissions in Recovery mode, then re-installing macOS. Shortly afterwards, when Big Sur was in beta in June 2020, Apple withdrew that support note and all reference to repairing permissions, although the tool is still available in Recovery mode even on Apple silicon Macs.

Running repairHomePermissions from Terminal in Recovery launches a GUI app to repair permissions on a selected Home folder on the Data volume. However, I strongly recommend that you don’t try using this, as you’ll end up with the user being locked out of every folder in their Home folder. I have tried it three times in virtual machines, and each time I have had to discard that VM because of the problems it caused.

Delete a corrupt preference file

Regardless of those, there are still occasions when preference files can cause problems. These typically occur when a corrupt or damaged preference file causes an app or other code to crash, usually when it’s being launched. Although these are now far less common, and the SSV ensures that system files can’t become corrupted as they did in the days before SIP, it’s useful to know how to deal with them.

On most occasions, a preference file can be deleted in the normal way, either in Finder or Terminal, and it won’t return until that app is run again, as it won’t currently be managed by cfprefsd. The alternative is to use defaults:
defaults delete com.mycompany.appname
deletes all the key-value pairs within the preference file for com.mycompany.appname, leaving just the empty property list. This has the advantage that it can be used when cfprefsd is managing that file’s contents, so should always be reliable. Provided the app handles preferences correctly using UserDefaults, it should be able to repopulate the empty property list the next time that app is launched.

One significant caution is when working with files inside ~/Library/Containers,~/Library/Group Containers,~/Library/Daemon Containers and similar managed folders. Because these form sandboxes, macOS manages them differently and tampering with their contents is likely to have unintended effects, so is best avoided, although the defaults command should still be safe.

Summary

• Repairing disk permissions on system files ceased with SIP in El Capitan.
• Repairing permissions on Home folder preference files is no longer recommended by Apple, since Big Sur.
• Safe and robust deletion of contents of a preference file can be performed using defaults delete.
• Don’t tamper with files inside ~/Library/Containers, ~/Library/Group Containers and similar folders.
• Never be tempted to run repairHomePermissions in Recovery mode.

With the Paris Commune crushed in 1871, and order being restored to France under the new Republic, the Pissarros returned to live a more settled life in Louveciennes again, after the shock of discovering that most of his 1500 or so paintings had been damaged or destroyed by occupying Prussian soldiers. There Pissarro lived close to Alfred Sisley, and the two often painted in company. Renoir’s mother also lived in the village, enabling the three painters to meet frequently.

Among Pissarro’s favourite motifs in this post-war period were numerous views of the Route de Saint-Germain and other roads around Louveciennes, and the River Seine at Bougival.

Less known are his watercolours, such as this view of Louveciennes, Route de Saint-Germain from 1871, and are reminiscent of the paintings of Johan Jongkind.

Pissarro painted this woodland view of an Avenue in the Parc de Marly in the autumn of 1871. It looks towards the village of Marly-le-Roi from the Port du Phare, inside the grounds of the Château de Marly. His skilful use of staffage draws the eye towards the far end of the avenue. The artist seems to have sold this painting quite quickly to an unknown buyer, from whom Durand-Ruel bought it in early 1873.

Alfred Sisley also painted here en plein air, as seen in The Seine at Bougival from 1872. The water surface is mirror-smooth, and Sisley has been careful to paint the reflection of the buildings with optical precision.

This is Pissarro’s wintry scene of The Post-House, the Route de Versailles, Louveciennes, Effect of Snow from 1872. This looks from the ‘Royal Gate’ of the Château de Marly towards the post-house, a landmark featured in several of his works from this period. This painting was bought that Spring by Durand-Ruel, who sold it a year later to Jean-Baptiste Faure, the opera singer, Pissarro’s first collector and Sisley’s enduring patron.

Pissarro must have taken delight in the weird forms of the trees in this Chestnut Grove at Louveciennes, painted in 1872. In the far distance is the massive warm cream stone of Marly Aqueduct.

Although the Pissarros were able to live on the money generated by Camille’s painting, they must have got by in relative poverty. However, in 1872, he sold four stretched canvas overdoor panels depicting the seasons to the banker Achille Arosa for 100 Francs each. Pissarro tried to buy them back when they came up for auction in 1891, but despite appealing to Vincent van Gogh’s brother Theo, they were sold for just over a thousand Francs to the Bernheim-Jeune Gallery, and have remained in private collections since.

In April 1872, the Pissarros moved from Louveciennes to Pontoise, where they rented a house and Camille established his studio.

Sisley wasn’t as prolific as Pissarro in either ‘road’ or snow scenes. His Snow on the Road, Louveciennes (1874) clearly comes from the same school, but his trees and buildings remain distinctive.

Sisley’s Aqueduct at Marly (1874) shows the massive form of this aqueduct which appeared in the distance in Pissarro’s Chestnut Grove at Louveciennes above. This and the nearby Machine de Marly, which Sisley also painted, were part of a monumental hydraulic network built in the 1680s for Louis XIV, to supply water to the Château de Marly and the royal gardens of the Palace at Versailles. The stone tower at the right end of the aqueduct is the Tour de Levant, used by Prussian troops as a vantage point for observing the besieged city of Paris, a point that won’t have escaped Sisley’s attention.

Sisley’s Forge at Marly-le-Roi from 1875 shows the village blacksmiths at work.

In 1876, Félicien Rops must have visited one of the popular bathing resorts nearby, to paint his Sunday in Bougival. This shows a lecherous old man watching two young women preparing to bathe there, a mere 15 km (10 miles) from the heart of Paris.

By this time, the Impressionists had moved away from Louveciennes, and were painting elsewhere.

Although Sisley was now living near Sèvres, he must have returned in about 1879 for one last painting in front of the motif, on The Road from Versailles to Louveciennes. This is an example of his more sketchy plein air paintings from his time at Sèvres, and a more traditional perspective view of a road of the time. This section of the road is close to Louveciennes, on the main route between Versailles and Saint-Germain-en-Laye.

At that point, the Impressionists finally left Élisabeth Louise Vigée Le Brun to rest in peace.

For the last seven years or so there have been many folk complaining that Spotlight local search hasn’t been finding the files they know are there. Many have resorted to repeatedly rebuilding its indexes, usually without success. Last week, thanks to Jürgen, Drew, aldous and others who have contributed, we have discovered one cause. A bug that appears to have been introduced in macOS Mojave, and is still present in Tahoe 26.0.1, that prevents Spotlight from indexing any of the contents of plain text files that start with certain characters.

Jürgen stumbled across the first example, with files starting with the two capital letters LG. At the time, that seemed extremely unusual and unlikely to affect many files. Then Drew added HPA and Draw to the list of forbidden characters. What looked like a rare event was becoming increasingly commonplace, and that list can only grow. How many indexing failures it could account for is impossible to guess.

Piecing together the evidence, it looks like this bug is inside the standard macOS RichText.mdimporter, now embedded in the Signed System Volume in /System/Library/Spotlight and at version 6.9 (350), as it has been since Sonoma (Ventura 13.7.8 has build 345.60.106, although that also suffers this bug). What happens is that saving a text file starting with forbidden characters correctly triggers Spotlight’s indexing service. That identifies the file as having the UTI public.plain-text and hands it over for its contents to be indexed. But the indexer inspects those first few characters, decides it’s a different type of file altogether, and promptly returns an error 4864 for an NSCoderReadCorruptError without going any further.

Apart from the text content not being added to Spotlight’s indexes, and a few lines buried in the Unified log, there are no indications of anything going wrong. If you test the importer using
mdimport -t -d3 filename
the file appears to import correctly, but that command doesn’t give any insight into the import of its contents, only standard attributes such as the filename that are indexed separately.

It was Drew who first suggested a plausible reason for this failure, confirmed by aldous: prior to attempting to index the text contents, Spotlight’s service was using a completely different method to check the type of the contents, the ‘magic’ database used by the file(1) command.

file(1) is an old Unix utility dating back to 1973 or earlier, operating independently of UTIs that were adopted in Mac OS X 10.4 Tiger 20 years ago. Rather than relying on a type assigned to a file, it ‘sniffs’ the contents, particularly the first few bytes of data, and uses a sprawling set of ad hoc rules to guess the file type. It turns out that files starting with the characters Draw were characteristic of a binary vector graphics format used by the !Draw app for RISC OS 2 in 1989. Rather than believing the file’s UTI for one of the most common types of files in macOS, Spotlight’s indexer therefore decided that it was trying to import file data that must now be as rare as hens’ teeth, and wouldn’t go any further.

If you’re sceptical about this coincidence, open the acorn magic data in /usr/share/file/magic in a text editor, and you’ll see the file opening string of Draw identified as RISC OS Draw file data. There are 332 other magic data files containing similar rules for identifying file types. I leave it as an exercise to the Unix wizard to build a list of all those that could cause similar problems with Spotlight indexing.

When this bug hunt started and it affected just LG and HPA, it was fairly esoteric and faintly amusing, at least as long as you didn’t write about your LG TV, high pressure air or Horizontal Pod Autoscaling. When Draw was added, and all those 333 magic files piled in, I realised how extensive this could be, and how little testing can be performed on Spotlight indexing and search.

Given that about eight years ago an Apple engineer wrote code for the RichText.mdimporter in macOS that introduced testing against some or all of the magic database, wouldn’t you have thought they’d test and debug that against test cases, such as text files starting with characters (mis)recognised by magic rules? And maybe occasionally over subsequent years and new versions of macOS, wouldn’t revised versions of the importer be tested again?

Apple likes Spotlight to be opaque to the user, for it to ‘just work’. There’s almost no documentation even for developers, and tools provided are strictly limited in what they can do, as demonstrated here in the case of mdimport. That’s all very well until Spotlight doesn’t work and no one outside Apple can do anything about it. Third-parties can’t even write custom mdimporters to do the job properly, as those bundled in macOS take priority.

If this was the first time that Spotlight indexing had let us down, I might feel more charitable. But between macOS Catalina 10.15.6 in July 2020 and Big Sur 11.3 in April 2021 macOS was incapable of indexing the content of any Rich Text files. There are still many documents that haven’t been indexed as a result. Those whose contents haven’t been indexed as a result of this bug will similarly be excluded from search until they too are reindexed by a fixed mdimporter. For Intel Macs that won’t be supported by macOS 27, that could well be forever.

When the prolific portraitist in pastels Élisabeth Louise Vigée Le Brun retired to live near Paris, she chose a small hamlet to the west of the city, between the palace at Versailles and Saint-Germain-en-Laye, Louveciennes. She died there in 1842, and is buried in the graveyard not far from her house.

Twenty-seven years later it became the focus for a group of friends, who went on to become the core of the French Impressionists. For the next few years Louveciennes and the adjacent villages of Bougival and Marly-le-Roi were to appear in well over a hundred of their paintings, a few of which I show this weekend.

Just beyond Chatou, the River Seine sweeps to the right in a bend with a series of long islands with popular bathing houses, among them the famous La Grenouillère. In the summer of 1869, Auguste Renoir was living at his parents’ house in Louveciennes, just to the south of this bend, where Camille Pissarro and his family were renting a house. He visited Claude Monet and his family, who were living near Bougival, also on that bend, and they often painted together.

Some of the formative moments in Impressionism if not European art occurred when Monet and Renoir visited La Grenouillère.

Renoir painted at least three different views of La Grenouillère that summer: that above is now in Stockholm, and that below, which is most similar to Monet’s, is in the Oskar Reinhart Collection in Switzerland; the third (not shown here) is in the Pushkin Museum in Moscow. Originally conceived as plein air sketches preparatory to more finished paintings for submission to the Salon the following year, they came to define these brilliant shimmering images formed from high chroma brushstrokes as Impressionist style.

If Impressionism has to have a single moment of birth, it’s surely in the summer of 1869 at La Grenouillère.

Monet’s Bathers at la Grenouillère is his early statement of his Impressionist agenda. The pair realised that Impressionism was about these sketched instants. This also reveals Monet’s preference for modern pigments, as most of the brighter mid-blues here use cobalt blue, introduced earlier in the nineteenth century.

In addition to Renoir, Pissarro and Monet, Alfred Sisley maintained a studio nearer the river in Bougival, where the four artists painted, starved and fought off despair together.

Pissarro painted a succession of views of the roads around the village. His Road to Versailles at Louveciennes (Snow Effect) (1869) is typical of his earlier ‘road’ paintings, showing an avenue of tall, bare-branched trees, brushed in coarsely.

The following winter his paintings concentrated on road scenes around Louveciennes, a theme which continued for many years, spanning the seasons.

As many artists before him, Pissarro used trees to frame his motifs in repoussouir, but during the late 1860s they started to invade more central areas of the canvas. In about 1869, in his Winter Landscape at Louveciennes for the first time tree trunks and branches spread across his canvas, breaking up the motif behind into small sections.

Pissarro’s Houses at Bougival, Autumn is clearly dated 1870, although by that time he had moved from Louveciennes. It is also thought to have been exhibited at the Salon that year, suggesting it may have been started in late 1869.

Like Pissarro, Sisley started depicting the streets of suburbs, including Early Snow in Louveciennes. This has been dated to 1870, although it appears more likely that it was painted en plein air late the previous year.

Following the outbreak of the Franco-Prussian War, in September 1870 the Pissarros’ house in Louveciennes was requisitioned by the invading Prussians. The family fled first to their friends in Montfoucault, then in December travelled on to England, where they settled in Norwood, at that time an outer suburb of London. When in England, Pissarro met Paul Durand-Ruel, who became his dealer, and Claude Monet, who had also fled to London.

Bougival was also overrun by Prussian soldiers, who commandeered Sisley’s studio; many of his early works were lost, as Pissarro’s were in Louveciennes, just over a mile away. The Sisleys were forced into the city of Paris, and despite Alfred’s British nationality, they remained trapped through the siege of the city into the following year. Worse still, the Sisley family business collapsed and his parents were in no position to support the artist.

Here are this weekend’s Mac riddles to entertain you through family time, shopping and recreation.

1: A red Canadian named by Jef and after John came in 1984.

2: A wonder for cooking led by Larry came in 1993.

3: This fruit from Newtown flopped between 1996-97.

To help you cross-check your solutions, or confuse you further, there’s a common factor between them.

I’ll post my solutions first thing on Monday morning.

Please don’t post your solutions as comments here: it spoils it for others.

One of the most fundamental changes brought by the Mac was the ability to open and edit files without having to explicitly specify which app to use. Instead of typing in a command telling an app to open a file, we can simply double-click the file and the Mac already knows which app to use. This relies on every file having a type, and the association between file types and apps. This article explains how that is now accomplished in macOS.

History

Classic Mac OS relies on two four-character codes assigned to every file designating their creator and type. An app has a type of APPL, and a text file a type of TEXT. A text file created by the TeachText app might have a creator code of TTXT and a type code of TEXT. Double-click on that file and the Finder looks for the app (with a type code of APPL) with the creator code of TTXT, and asks that to open the file. Associations between app creator codes and file types are also built into the Finder’s Desktop databases to relate icons with file types, forming the heart of the Desktop metaphor.

Although Mac OS X retained type and creator codes, early versions relied on filename extensions to determine the type of files, a feature of older operating systems and NeXTSTEP. Apple therefore invented a new system for identification and classification of file types and more using Uniform Type Identifiers, introduced in Mac OS X 10.4 Tiger. They have since been incorporated into a generalised UTType structure in macOS 11 Big Sur.

UTI

The standard system in macOS is based on a Uniform Type Identifier, or UTI, like public.plain-text for a plain text file, and public.jpeg for a JPEG image.

UTIs use a structured hierarchical taxonomy forming a vast interconnected tree. For example, when I write a file of Swift source code, the .swift file has the type public.swift-source, a specialised type of public.source-code, which is public.plain-text, which is public.text, and in turn both public.data and public.content. When I open that file, LaunchServices first looks for an editor for public.swift-source files, but can ascend the UTI tree as necessary and use an app designed to open text files of public.text more generally. Some of the more frequently encountered UTIs are shown in the diagram below, which you’ll probably need to expand to full screen to read clearly.

Determining the UTI

It’s often claimed that macOS depends on filename extensions to determine different types of file, but that’s not correct: it’s more capable, and uses MIME types when downloading from the Internet, and ultimately relies on UTIs.

This is easily demonstrated in Terminal. Type the following command
touch notypefile
to create a new file in the current directory without any extension or other clue as to what it is. Then look in the Finder’s Get Info dialog, and you should see that macOS has already assigned it a default type associating it with a default editor. Inspect that file using my free utility Precize, and you’ll see that it has a UTI (listed in the Type entry) of public.data.

Now give it an extension unknown to macOS, such as .xyz, and inspect it again with Precize: its type has changed to something more cryptic like dyn.ah62d4rv4ge81u8p4. That’s a dynamic UTI, created on the fly by macOS to distinguish it as having a unique type, described in Get Info simply as a Document, but still with its default associated editor.

Every item in your Mac’s file system has a UTI to tell LaunchServices what to do when you try to open it, for instance by double-clicking its icon. You may find an exception to this, from a longstanding bug dating back to OS X 10.5 in 2007: some files may not return a UTI, but a NULL instead. This seems to be confined to sockets, which might appear to be files but aren’t really.

Discovering the UTI

Unfortunately, although discovering UTIs is key to dealing with documents which are treated as having the wrong type, there’s no easy way to find a file’s UTI in macOS. Thankfully you don’t need long reference lists to find out key information such as what a filename extension or MIME type represents in terms of a UTI: it’s all contained within macOS, if you know how to look using one of the tools listed below.

My own utility for working with UTIs is UTIutility. Its main window lets you enter an extension like xls, and tells you all macOS knows about that and its corresponding UTI. Alternatively, you can open its Crawler window and get it to list all the UTIs it comes across in the selected folder. That can take a long time to work through large folders, or those loaded with UTIs like /Applications, but its results are revealing.

The correct answer to the question of what determines a file’s type is therefore a whole list:

• UTI, e.g. com.adobe.pdf,
• filename extension, e.g pdf,
• OSType, e.g. PDF,
• MIME type, e.g. application/pdf, or
• Pasteboard type, e.g. Apple PDF pasteboard type.

While you can change a file’s type directly by giving it a different UTI, it’s far simpler to do that indirectly by changing its extension to one correct for the type, such as txt or text for a text file. MIME types are mainly used for Internet file transfers, and Pasteboards are used when copying chunks of data using the Clipboard, which relies on the same basic system.

Other uses

In addition to LaunchServices making the association between the type of file you want to open and the app to use for that, UTIs are used extensively in macOS to determine how to handle different types of file. Among the more important are QuickLook, when deciding which generator to use to build a file’s thumbnail and preview, and Spotlight, when deciding which importer to use to index the contents of a file. Indeed, UTIs are so central to Spotlight that the command used in Terminal to inspect a file UTI is mdls, part of Spotlight.

Tools

Thomas Tempelmann’s free Launch Services features an excellent UTI browser.
Precize and UTIutility are free from their Product Page.

Apple documentation

UTI overview (archived)
Framework doc (current)
System-declared UTIs (current)
UTType (current).

There’s a long and ancient tradition of performing what would now be considered to be crude experiments in physics and chemistry, most commonly aimed at transforming one substance into another. Founded on flawed principles such as matter consisting of four elements, its best-known goal was the transformation of ‘base’ metals like lead into precious metals, particularly gold. In their quest for this, alchemists developed exotic equipment including a range of blown glass such as alembic vessels, trademarks of alchemy.

At least in popular perception, alchemy was one of the ‘dark arts’ and allied with witchcraft and sorcery. Myths like the rejuvenation of Jason’s father Aeson by the sorceress Medea have been depicted as involving both.

In the late seventeenth century Domenicus van Wijnen painted his account of Medea Rejuvenating Aeson, invoking both alchemy and witchcraft. Medea, naked and reclining in Hecate’s golden chariot, points her wand at the body of Aeson lying on the ground as she casts a spell. A glass sphere above her contains a small devil and shoots a trail of flame and sparks like a rocket. Medea is assisted by four putti and has what appears to be Hecate herself behind her, and a full moon is rising above the horizon. Scattered around the scene are objects associated with the ‘dark arts’, including a glass cauldron, a jar of brown liquid, a sacrificial knife, old books, and a burning candle.

Bartolomeo Guidobono’s Medea Rejuvenates Aeson from about 1700 is more of a puzzle to read, as Medea, now dressed in an unkempt and wild manner, is accompanied by two men. The near-lifeless and pale body of Aeson rests behind her, but a younger man, possibly the rejuvenated Aeson, is materialising under a table. There is now a panoply of symbols associated with magic, including a snake and toad, large tomes of spells on top of which is a lizard, an open fire on a small stand, and an assortment of more normal animals including a dog, fox, and deer. The table in the background has further magical equipment, such as an orrery, and a bat is flying to the right of Medea’s head.

A similar combination is seen in visual accounts of part two of Goethe’s Faust. When Faust is taken unconscious into his old study, Mephistopheles poses as Faust and interviews his young student Wagner, and the latter uses alchemical processes to create a homunculus. This is the one scene from this second part to prove popular with artists.

Alfred van Muyden’s illustration of Scene: Laboratory, Wagner Creates the Homunculus from about 1840 is an early example referring to popular imaginings of such alchemical processes.

This anonymous version of Homunculus, Faust part 2 is simpler in conception.

Franz Xaver Simm’s Homunculus in the Vial from 1899 uses light very effectively.

Moritz Retzsch’s line drawing for an illustration from 1836 is more detailed and better-developed. Wagner holds the large glass vial in which the homunculus has been created, as Mephistopheles points towards the collapsed figure of Faust in his study, at the left.

With the age of Enlightenment, alchemy was viewed as a proto-science to be debunked with the arrival of early modern chemistry and physics.

Today’s concept of alchemy as a mixture of magic and charlatanism hadn’t been established at the time that Joseph Wright of Derby was painting. The Alchymist, in Search of the Philosopher’s Stone, Discovers Phosphorus, and Prays for the Successful Conclusion of his Operation, as was the Custom of the Ancient Chymical Astrologers (1771-95), which summarises its narrative in the title, is comparatively sympathetic to alchemy.

Wright created this image in 1771 from a variety of sources, including drawings provided by Peter Perez Burdett from his new chemical laboratory in Liverpool, and classical engravings. It is particularly appropriate in depicting the purification of phosphorous, which was seen as a productive and positive outcome from the ancient pursuit of alchemy.

By the late nineteenth century, when Elihu Vedder painted The Dead Alchemist (c 1868), that had changed. Vedder shows a lone figure, slumped and apparently dead against a carved chest. Scattered around him is the equipment that might previously have been used by an alchemist.

The eccentric Belgian artist Félicien Rops conjured with various images of devils and witches. One of his more gentle paintings of the occult is The Incantation (c 1878). A Faustian character sits in front of an open copy of Compendium Maleficarum, a witch-hunter’s manual first published in Latin in 1608. He’s surrounded by the tools of his trade: alembics from alchemy, a sprig of mandrake, a pelican, an owl, and a black cat is behind his chair. He has just conjured up a naked young woman, who is popping out of a picture frame. It all seems good fun, as if witchcraft and alchemy should be hobbies for every family.

In John Collier’s The Laboratory (1895), there’s clearly a narrative between the old alchemist and a young woman, who is trying to take an object from the man’s right hand. This may be a reference to a written narrative that Collier was exploring prior to painting his real problem pictures.

Timestamps on files and folders are important, and can be used for many different purposes, from sorting files to find the most recent, to providing evidence in court. Each file (and directory) in APFS has four separate timestamps you can use:

• Created, termed in APFS create_time, gives “the time that this record was created”.
• Modified, mod_time, “the time that this record was last modified”.
• Last opened, access_time, “the time that this record was last accessed”.
• Attributes Modified, change_time, “the time that this record’s attributes were last modified”.

Although the Finder only displays those to the nearest second, the macOS API readily provides fractions of a second, commonly resolved to milliseconds, and the raw values are saved as nanoseconds since 00:00 UTC on 1 January 1970.

The first three are those most commonly used, although the last can be relevant in backups in particular. If you want to see which file in a folder is the oldest there, look for the oldest time Created. If you want to know which was most recently changed, look for the latest Modified time.

Where you must be careful is in interpreting those dates, as it’s easy to make assumptions that may not always work. The first confounding factor is that files can change without updating the Last opened time.

Apple’s APFS reference states that access_time is updated according to the behaviour set by that volume’s APFS_FEATURE_STRICTATIME setting. “If this flag is set, the access_time field of j_inode_val_t is updated every time the file is read. Otherwise, that field is updated when the file is read, but only if its value is prior to the timestamp stored in the mod_time field.”

Does APFS in macOS currently set the APFS_FEATURE_STRICTATIME for its volumes?

You can see how that works in a simple demonstration. Create a new text file in TextEdit and add a line or two of text to it, then save it. In the Finder, Created, Modified and Last opened timestamps will now all give the same time and date. Leaving that file open in TextEdit, wait a couple of minutes, then add another line to the file and save it again. In the Finder, the Modified time will be updated, but not the Last opened time, because the file hasn’t been opened and read again. Close the file, wait another couple of minutes, and open it again. You should see its Last opened time update, indicating that APFS_FEATURE_STRICTATIME is set for that volume.

My example is even more extreme. According to these timestamps, this file was Created on 13 July, and hasn’t been opened since. However, it was modified without being read on 23 September. If it’s opened and read now, it’s Last opened time will be updated whatever the APFS_FEATURE_STRICTATIME setting.

There’s another confounding factor that makes this even less reliable: QuickLook. Although its thumbnails and previews are constructed using file data, that access doesn’t affect either the Modified or Last opened timestamps, and opening and reading a QuickLook Preview isn’t recorded anywhere in a document’s attributes. So it could be extremely misleading to assume that a file hasn’t been viewed just because its Last opened timestamp hasn’t changed.

If you do want to use the timestamps on files or folders, it’s essential to know their limitations and behaviours, otherwise you could draw the wrong conclusions.

At the height of his career, Johannes Vermeer’s paintings seem to have secured good prices, thanks to an affluent collector in Delft. They also appear to have been a significant influence on others, including Gabriël Metsu.

Music features in several of Vermeer’s paintings, in The Concert (c 1663-66) more particularly than any other. Two ladies are making music, one playing a decorated harpsichord (or similar), the other singing. In the left foreground is a cello resting on its back. Tragically, on 18 March 1990 this and a dozen other works were stolen from the Isabella Stewart Gardner Museum in Boston, MA, and it remains unrecovered.

Soft edges are obvious in Vermeer’s renowned portrait of a Girl with a Pearl Earring, from about 1664-67. Seen even closer up in the detail below it’s obvious that he has softened most of its edges to some degree, even on highlights such as the white reflections on the pearl itself and the girl’s eyes.

His Mistress and Maid from about 1664-67 also has many soft edges, particularly those of the maid in the left distance, whose head and forearms are blurry. The crispest edges are those of the mistress’s forearms, particularly the left as it crosses her clothing. These also appear consistent with depth of field effect.

Vermeer painted at least two works showing women writing, of which the earlier is A Lady Writing a Letter from 1665-1666. The fur trimmings on her golden jacket confirm this is no country bumpkin, but the lady of an affluent and well-educated house. Rather than looking down at her quill, she stares the viewer out, her faint smile of confidence lit by sunlight coming through the window off to the left.

In Vermeer’s late The Art of Painting from about 1666-68, greatest sharpness is again slightly away from the geometrical centre of the canvas, in the woman holding a wind instrument, as shown in the detail below. The high tonal contrast between the marble tiles on the floor is softened in the foreground, and sharpens as they recede deeper into the picture, as would be expected in depth of field.

They also appear in Vermeer’s late painting of The Astronomer, from about 1668. He is studying his celestial sphere marked with the symbols of the constellations.

In The Geographer, visibly dated the following year, the figure holds a pair of dividers over an unidentifiable chart, with a fine globe tucked away behind and above him.

While there are some instances where Vermeer’s blurring could be consistent with motion, most of these paintings appear to show depth of field effects as might be observed through a lens with a shallow depth. They could also be consistent with his use of an edge hierarchy for compositional emphasis.

Recently, several attempts have been made to explain how Vermeer came to use blurring so successfully. One story that has gained some traction is that he used optical devices such as a camera obscura to lay out the forms within each of these scenes, a theory that has been repeatedly claimed by David Hockney among others. Most recently, though, it was realised that alone was insufficient to explain all the optical phenomena modelled so well in these paintings, and it has been proposed by Hockney and Tim Jenison that the artist coupled a concave mirror with another mirror, a system that took Jenison five years to develop and test.

It’s perhaps unsurprising that there’s no evidence whatsoever that Vermeer possessed or used a camera obscura or other optical device, although he was a close friend of the pioneer lens maker Antonie van Leeuwenhoek, at a time when there was considerable interest in optics.

Johannes Vermeer died in 1675, as the Dutch Golden Age was drawing to an end, and the market for paintings collapsed.

References

Vermeer’s popularity in the last century has ensured extensive supporting material. The following is a small selection of what I think is the very best.

Essential Vermeer, Jonathan Janson’s superb site

Gaskell I and Jonker M eds (1998) Vermeer Studies, Yale UP. ISBN 0 300 07521 9.
Liedtke W (2008) Vermeer, the Complete Paintings, Ludion/Harry N Abrams. ISBN 978 90 5544 742 8.
Liedtke W (2009) The Milkmaid by Johannes Vermeer, Metropolitan Museum of Art, New York. ISBN 978 1 58839 344 9. (Available for download from here.)
Wheelock Jr AK (1997) Vermeer, the Complete Works, Abrams. ISBN 978 0 8109 2751 3.

Alain Jaubert, Palettes DVD: Le siècle d’or des Pays-Bas, Le grain de la lumière, Editions Montparnasse.
Tracy Chevalier’s fictional Girl with a Pearl Earring (1999) is also available as a movie under the same title (2003).

There’s a bug in Spotlight that can prevent it from indexing any of the contents of susceptible text files. This has been present since macOS 13 Ventura if not before, and is still present in Tahoe 26.0.1. I didn’t discover this myself, though: it was reported to me by Jürgen, to whom full credit is due. It’s also one of the strangest bugs I’ve come across, and all depends on two letters.

Demonstration

To demonstrate this bug, all you need is a single UTF-8 plain text file, created by TextEdit or any other app capable of saving plain text. Start the text with the two characters L and G, both in capitals. Then add one or more distinctive words, such as
LG syzygy

Save that file to a folder that you know is indexed and searched by Spotlight, then a few seconds later try searching for the word syzygy in its contents. Extend this as much as you want, maybe appending the whole of one of Charles Dickens’ novels, but no matter how you search for its contents, that file will never be found. If you want to get more serious, use that text file in my Spotlight test app SpotTest, and it will also be unable to find that file.

This only works with plain text files, not Rich Text, PDF or HTML. It’s also sensitive to those two letters. Set one of them in lowercase, preface them with a space, or substitute a different letter, and the contents of that file will then be indexed correctly and searchable as normal.

Affected macOS

I have tested this in virtual machines going back as far as macOS 13 Ventura, and it’s present in them all. If you have access to an earlier version of macOS, I’d be interested to know whether it affects that as well.

Cause

The two UTF-8 characters concerned, 4c 47, don’t appear to be anything special that could be misinterpreted.

Although it’s not easy to distinguish failure to index from search errors, saving a test file does result in repeated reports of an error that could cause Spotlight to fail when trying to index the file, for example the log entries
30.946740 mdwrite Decoding error: Error Domain=NSCocoaErrorDomain Code=4864 UserInfo={NSDebugDescription=[private]} for [private]
30.951004 mds Decoding error: Error Domain=NSCocoaErrorDomain Code=4864 UserInfo={NSDebugDescription=[private]} for [private]

Error code 4864 is NSCoderReadCorruptError, implying that the presence of those two characters at the start of a text file may be triggering a bug in RichText.mdimporter, the importer module shipped in macOS that’s responsible for indexing plain text files.

My current hypothesis is therefore that text files starting with the characters LG are failing to have their contents indexed correctly because of a bug in RichText.mdimporter.

History

This isn’t the first bug in the RichText.mdimporter. In macOS Catalina 10.15.6, the same mdimporter (then build 319.60.100) introduced a bug that broke indexing of Rich Text (RTF) files. That was perpetuated through early releases of Big Sur until it was finally fixed in RichText.mdimporter build 326.11 in Big Sur 11.3.

Because text files starting with the characters LG are exceedingly unusual, this bug appears to have been left in RichText.mdimporter for a great deal longer.

I will be reporting this to Apple in Feedback later this month. Please feel free to file your own Feedback if you can spare the time.

Summary

• In macOS 13 to 26, plain text files starting with the characters LG cannot be searched for their contents.
• This appears to be the result of a longstanding bug in RichText.mdimporter in macOS.
• If those characters are altered, or prefixed by a space, indexing and search behave normally.

I’m very grateful to Jürgen for drawing this to my attention.

Apple has just released an additional out-of-cycle update to XProtect, bringing it to version 5321. As usual, it doesn’t release information about what security issues this update might add or change.

This version has no changes from 5320 in its Resources property lists or Yara file. Indeed, the version number given in XProtect.meta.plist remains 5320, although those given in the bundle’s Info.plist and version.plist are 5321.

You can check whether this update has been installed by opening System Information via About This Mac, and selecting the Installations item under Software.

A full listing of security data file versions is given by SilentKnight and SystHist for El Capitan to Tahoe available from their product page. If your Mac hasn’t yet installed this update, you can force it using SilentKnight or at the command line.

If you want to install this as a named update in SilentKnight, its label is XProtectPlistConfigData_10_15-5321

Sequoia and Tahoe systems only

This update has already been released for Sequoia and Tahoe via iCloud. If you want to check it manually, use the Terminal command
sudo xprotect check
then enter your admin password. If that returns version 5321 but your Mac still reports an older version is installed, you should be able to force the update using
sudo xprotect update

During his career in Delft, Johannes Vermeer had been respected as an artist, but soon after his death at the end of the Dutch Golden Age he slipped quietly into obscurity, alongside many hundreds of others. A few connoisseurs maintained an interest in his work, but it wasn’t until the middle of the nineteenth century that he was rediscovered. Since then his few remaining paintings have become among the most revered in the European canon.

Vermeer was born in the city of Delft in 1632, where he took over his father’s business as a dealer in paintings. He also trained as a painter, and at the end of 1653 was admitted to the city’s Guild of Saint Luke. The following year Delft was struck by a catastrophic explosion in a gunpowder store, destroying a large section of the city and its occupants.

Vermeer’s Christ in the House of Martha and Mary is his largest surviving painting, and probably one of his earliest, dating from about 1654-56. It’s unusual among them for its religious theme.

By about 1657-58, when he painted Officer and Laughing Girl, he had found form in the compositional approach for which he is most famous. Figures going about their everyday lives are seen in the daylight cast from windows on the left. The map depicted so meticulously has been identified as that made of Holland and West Friesland by Willem Blaeu and Balthasar Florisz van Berckenrode. Unfortunately, no other complete copy of that map has survived, but its second edition was published by Blaeu in 1621, and that’s believed to be on display here, as shown in the detail below.

Some of these paintings feature heavy curtains in the foreground, drawn back to reveal Vermeer’s subject behind. Among those is his Girl reading a Letter at an Open Window (c 1658), where its railed curtain gives an air of intimacy, suggesting the viewer is peeping past the curtain and gazing in at real and private life.

The Milkmaid, probably from about 1658-59, is perhaps Vermeer’s first true masterpiece, and introduces the optical effects for which he is now best-known.

A milkmaid is pouring milk from a jug, beside a tabletop with bread. In the left foreground the bread and pots rest on a folded Dutch octagonal table, covered with a mid-blue cloth. A wicker basket of bread is nearest the viewer, broken and smaller pieces of different types of bread behind and towards the woman, in the centre. Behind the bread is a dark blue studded mug with pewter lid, and just in front of the woman (to the right of the mug) a brown earthenware ‘Dutch oven’ pot into which the milk is being poured. An ultramarine blue cloth (matching the woman’s apron) rests at the edge of the table.

The woman, seen in three-quarter view, wears working dress: a stiff, white linen cap, a yellow jacket laced at the front, a brilliant ultramarine blue apron, and a dull red skirt underneath. Her right hand holds the handle of a brown earthenware pitcher, which she supports from below with her left hand. Her work sleeves are pushed up to lay both her weathered forearms bare to the elbow. Her strong-featured face and eyes are cast down, watching the milk as it runs into the pot.

More remarkable still is the visible blurring.

Edges and detail are sharpest around her left shoulder and upper arm, and soften as you look away towards her hands and the pitcher. Highlights on that pitcher and the pot below it are also decidedly blurry, suggesting this is intended as a depth of field effect.

Bread and other objects on the table in front of the woman also show controlled use of blurring, most obviously in the highlights on the wicker basket.

At some time around 1660, Vermeer painted a couple of cityscapes that are his only surviving non-figurative paintings.

Above is his view of a street and its occupants in The Little Street, and below is his View of Delft waterfront. A third cityscape of a House Standing in Delft has been recorded but is now apparently lost.

His Woman Holding a Balance from around 1662-64 shows a young woman who is pregnant holding an empty balance in front of a collection of pearls and gold. Its focus is noticeably softer than his earlier paintings. The edges of the tabletop in the centre of the canvas and the woman’s left hand are the crispest, and those further from that are softer, as would be consistent with depth of field effects.

Similar effects are seen in Vermeer’s better-lit Young Woman with a Water Pitcher from the same period. Here the central focus is in the upper chest of the figure, where the edge between the split in her white mantle and the underlying deep ultramarine clothing is crispest, and the reflections on the pitcher and bowl are blurry, again consistent with depth of field. So too is the window, which could indicate motion.

Amazingly, this painting was bought by Henry Gurdon Marquand in 1887 for a mere $800, and became the first of Vermeer’s paintings to enter an American collection.

All of us at some time or other find our mind has gone blank and we can’t remember the password we’ve typed in so often before. Or the person who did know that password may no longer be there to recall it for us. At times like these we may need to gain access to a locked Mac. This article looks at how you can do that in an Intel Mac with a T2 chip, or an Apple silicon Mac, running Big Sur or later, in particular macOS Tahoe. If you want information for an older Mac or macOS, this article should be more helpful.

Keyboard

If you’re certain you entered the correct password but it was refused, check the Caps Lock key isn’t on, and check the Mac is using the correct language keyboard in the menu at the top right.

Firmware password (Intel only)

Intel Macs can be protected using a firmware password set and removed in Recovery, and that can normally only be removed if you know the password. If you don’t, the most reliable way to achieve this is to take the Mac to an Apple store, together with proof of purchase or ownership, and ask them to remove the firmware password.

Further information is in this support note, and in Mr. Macintosh’s article.

Don’t just guess

Trying to guess a Mac’s password is doomed to failure: you only have ten attempts before you have to try in Recovery, and an absolute maximum of fifty attempts in total before access to its Data volume is permanently barred, and that Mac has to be restored in DFU mode. Time intervals are also added between attempts, starting at a minute after the third attempt, and rising to eight hours with the ninth.

Once you realise you don’t know the password, click on the ? to the right of the password entry box. If you keep trying to guess, your attempts will soon be delayed by lock periods that grow up to eight hours.

The Mac will then offer you the best option for resetting the password. If the Mac was opted into iCloud Recovery, you’ll then be asked for details of the Apple Account.

This is now handled by the Recovery Assistant, which also helps you use the Recovery Key if iCloud Recovery wasn’t chosen.

If you don’t have Apple Account details or the Recovery Key, the remaining option is to wipe the Mac. That’s offered in the Erase Mac command in Recovery Assistant’s menu.

For these the Mac needs an internet connection. Further details are in this support article. If you’ve forgotten your Apple Account password, Apple’s support article here should help.

Missing owner

Those methods all assume that you’re the owner/user, have simply forgotten your login password, and can recall your Apple Account details or Recovery Key. If the Mac belonged to someone who’s no longer there, and you don’t have access to their Apple Account, you won’t be able to use those options.

There are two further steps now available that you may find helpful. Provided your Apple Account has two-factor authentication enabled, if you’re unable to sign in or reset your password, you can ask Apple to perform account recovery. This isn’t immediate, but provided you can satisfy Apple that your request is genuine, it should prove possible.

As of macOS 12.1 and iOS/iPadOS 15.2, Apple has supported Legacy Contacts, but those must be set up before you need to use them. The Legacy Contact is then provided with an access key they can use in the event that you can’t because you’re dead. Apple also needs to see a copy of the death certificate before giving full access to the account for a period of three years. Full details are here.

Still no solution

If you want to access the Mac but not its contents, it’s straightforward to return Apple silicon and T2 models to factory condition by putting them into DFU mode and restoring them, as explained here. That may not always be a good step, though: when you try to set that Mac up again, it checks in with Apple. If it has been registered as stolen, you could find it becomes unusable.

If all else fails, get expert advice and help from Apple stores, authorised service providers, and from the many independent Mac technicians around the world who are often only too familiar with these problems.

Virtual machines

Depending on how they’re set up, macOS VMs can now support either iCloud Recovery, or a Recovery Key, provided the guest macOS can.

Apple has just released its weekly update to XProtect, bringing it to version 5320. As usual, it doesn’t release information about what security issues this update might add or change.

This version adds a single new Yara rule for MACOS.SOMA.OCENB, another for the vast Soma/Amos family.

You can check whether this update has been installed by opening System Information via About This Mac, and selecting the Installations item under Software.

A full listing of security data file versions is given by SilentKnight and SystHist for El Capitan to Tahoe available from their product page. If your Mac hasn’t yet installed this update, you can force it using SilentKnight or at the command line.

If you want to install this as a named update in SilentKnight, its label is XProtectPlistConfigData_10_15-5320

Sequoia and Tahoe systems only

This update has already been released for Sequoia and Tahoe via iCloud. If you want to check it manually, use the Terminal command
sudo xprotect check
then enter your admin password. If that returns version 5320 but your Mac still reports an older version is installed, you should be able to force the update using
sudo xprotect update

Professional artists have long used brushes to apply paint in their finished work, and many used hand-held sticks of pigment only when sketching in preparation. Charcoal has been widely used, with metal wire in silverpoint an alternative. In the sixteenth century, large deposits of graphite were discovered in Cumbria, England, following which graphite sticks and sheathed pencils became enormously popular among both amateurs and professionals.

Although it’s impossible to make any clear distinction between drawing and painting, those stick-based media are simple compared with oil paints, and seldom used in works comparable in their aims or sophistication to professional oil or watercolour painting.

The first changes in practice resulted from the French Revolution and Napoleonic Wars at the turn of the eighteenth to nineteenth centuries. Graphite was a strategic product, as it was used as a refractory in the manufacture of cannonballs, and supplies to France all but dried up. In 1795 Nicolas-Jacques Conté used a mixture of clay, graphite and other pigments to form sticks similar to pastels but significantly harder, referred to as hard pastels or Conté crayons.

As with charcoal and graphite sticks and pencils, Conté crayons were first used for preparatory sketching. By the middle of the nineteenth century, artists like Jean-François Millet extended their use into pastel paintings including his enchanting and mysterious The Cat at the Window from about 1857-58. Because of their hardness, Conté crayons were more amenable to sharpening, so could make finer lines and a richer range of marks.

Millet’s most famous painting in pastel and Conté crayon is this 1865-66 version of The Sower, a motif that was to recur in the hands of others for the rest of the century, and works perfectly in what were still relatively unconventional media.

Conté crayons, like pencil, charcoal and pastels, rely on mechanical adhesion rather than any polymerising binder. Specialised papers with roughened surfaces were marketed to improve their adhesion, but they share similar problems of longevity. However, at a time when mark-making was becoming popular, the wide range of effects available from sticks of pigment was an attraction: not only could the artist place bold strokes of colour over stumped-smooth areas, but they could also paint on textured grounds to great effect.

One of the masters of the Conté crayon was the Divisionist Georges Seurat, who used textured papers to give his paintings or drawings a highly granular appearance, as if they were photographs.

The rise of industrial chemistry and manufacturing industries in the nineteenth century brought other new painting sticks. Wax crayons effectively functioned as a low-temperature encaustic, and became popular in schools. They were adopted for resist techniques in watercolours, notably by John Singer Sargent, and some artists started using them in combination with other media.

Félicien Rops’ painting of a Hamadryad from about 1885 uses a wide range of media, drawn from those already popular among the illustrators of the day.

Another enthusiast for mixed stick media was Odilon Redon, for instance in his painting of Sîta from about 1893.

Although the mainstream Impressionists largely kept to oil on canvas, those on the periphery including Jean-François Raffaëlli were more experimental in their choice of media: his Parisian Rag Pickers from about 1890 was made using a mixture of oil paints and oil crayons.

The new generation of painters who started their careers in the early twentieth century used stick media increasingly. Egon Schiele was a prolific draftsman who used drawing techniques extensively in his painting. This work showing Krumau Town Crescent (Small Town V) (1915) is based on a drawing he had made the previous year, and uses the unusual combination of black crayon, gouache and oils.

For this Portrait of the Artist’s Wife Seated, Holding Her Right Leg, Schiele used just black crayon and gouache.

Some of the older generation joined in with unusual combinations of media. Late in his life, the former Divisionist Paul Signac painted many brilliantly coloured views of the south of France using combinations of watercolour and crayons, such as Antibes (1917) above, and The Old Port of Marseilles (1931) below.

On the other side of the Atlantic, also late in his career, Joseph Stella developed a novel drawing technique combining traditional metalpoint with modern crayons, which he used in his intimate portrait of Kathleen Millay from about 1923-24, above, and Eggplant, one of his last works, completed in 1944, below.

Metalpoint uses fine metal wire, most commonly silver, mounted in a holder, and is a slow and meticulous method of drawing or painting; its marks on paper are only faint to begin with, but they darken slowly as the fine tracks of silver tarnish.

Late in his career, Pierre Bonnard incorporated stick media in some of his paintings. The richly textured marks in this painting of his wife Marthe in The Bath from 1942 are strokes of coloured crayon, worked over gouache and pastels.

Paul Nash added both graphite and crayon marks to his 1937 watercolour of Three Rooms, a painting with strong graphic elements.

In the nineteen-twenties and -thirties, several art suppliers developed new types of crayon, using proper binders intended to allow more extensive effects and working, greater versatility, and improved longevity. These mixed conventional pigments with a bewildering array of waxes, oils and other substances, including:

• waxes and gums, to make crayons (sheathed in paper) and pencils (in wood);
• waxes, to make grease pencils;
• waxes and oils, to make lithographic crayons;
• mineral wax (paraffin), to make wax crayons;
• synthetic wax (polyethylene), to make water-dispersible wax crayons, such as Caran d’Ache Neocolor crayons;
• waxes and non-drying oils, to make oil pastels;
• waxes and drying oils, to make oil sticks and oil bars, that can form polymerised paint layers similar to conventional oil paints.

Their physical properties, determined by the binders used, in turn determine how they can be applied, appropriate grounds, fragility of the stick and its suitability for sharpening, whether diluents are organic solvents or water, and the depth and robustness of the resulting paint layer.

Unfortunately, even reputable manufacturers seem reluctant to provide detailed information on the lightfastness of pigments used, and to achieve high chroma level in attractive colours they often resort to pigments known to be fugitive on exposure to light. During the twentieth century in particular, this resulted in many fine paintings being made using media that rapidly became a conservation nightmare, either because the paint film has proved unstable, or their initially brilliant colours have faded rapidly.

Some types of media, in particular coloured pencils, have been vulnerable to irresponsible suppliers and artists who have put blind faith in products that have proved ephemeral. Sadly, few artists have obeyed the exhortation for the buyer to beware, and assessed the permanence of the media they have used in paintings which have been sold for large sums.

Among the most recent, and still unproven, media are oil pastels, which work into creamy layers, and undergo only limited hardening because they don’t incorporate drying oils like linseed or walnut. Their origins are controversial: first developed in Japan, and slightly later in Europe, it’s claimed that Pablo Picasso preferred them.

Oil pastels have certainly shown themselves capable in some unusual circumstances, such as Robert Clark Templeton’s court paintings, including his Sketch of an Overview of the Courtroom from 1971. Few courts would have even considered him using watercolours, for example, and for this case he chose modern and unobtrusive oil pastels. This sketch has been executed briskly, with effective use of gestures and marks.

Once a sketch has been laid down in oil pastels, it’s quick to work that up into a more detailed portrait like Templeton’s Drawing for CBS Evening News of Bobby G. Seale and others (1971).

Copyright restrictions prevent me from showing examples of stick media in the hands of modern artists, but I conclude by showing a couple of my own amateur efforts.

This Alpine landscape was painted in the studio using Sennelier oil pastels on Daler Rowney Ingres pastel paper.

This dawn view of the Pont Royal in the centre of Paris was painted with Caran d’Ache water-dispersible Neocolor crayons on paper. This uses base washes brought out from an initial dry crayon sketch, with superimposed texturing using dry crayon – something hard to achieve in watercolour.

Modern stick-based media look alluring, and are persuasively marketed by their vendors. However, those are seldom the traditional art materials suppliers that they might seem: most have been bought up by large companies that are primarily driven by increasing sales revenues, and may have little understanding of the requirements and problems of painting media.

Modern vendors are often secretive over the composition of their products, and although good standards exist for lightfastness, few publish data for their product ranges. Finally, their advantages in the making of art are often marred by the need to protect these paintings under glass.

Never take file attributes such as datestamps at face value. It’s only too easy to pull tricks by changing the system clock, and it’s straightforward to construct a bogus file with a made-up history.

In my case, I had a genuine excuse for a little gentle fabrication. As I’ve explained before, I use the saved versions of source code files I edit in Xcode to revert changes and similar. In this case, I wanted to merge and clean up saved versions in two copies of what would have been the same file, part of the source of LogUI. A couple of times during its development I have forked my source, and in this case have two files, one containing all the changes I made up to last summer, and the other with all those made since.

The first contains 120 saved versions dating back to the initial version on 8 July 2024, listed here in Revisionist.

The second took those on from 7 June 2025 up to last weekend, for LogUI build 77, released yesterday.

Some of the 130 versions were duplicates, so for efficiency I wanted to remove those and join the two sets of versions into one. I therefore dragged and dropped those two files onto Versatility, which saved all their versions into two folders. I then merged those into a single folder containing the versions I wanted to keep.

When Versatility reassembles those into a single file, it adds each version in numeric order, ignoring any gaps in numbering. As the version files from the first were numbered from 000 to 119, all I had to do was renumber those from the second from 200 to 209, put them into the same folder, and remove duplicate versions identified from Revisionist’s listings of the original versions.

When I dropped that composite folder onto Versatility it composed them into a single file, with 98 versions stretching from 8 July 2024 to 18 October 2025.

The date of creation of that file, which was actually 19 October 2025, is given as 7 June 2025, with a date of last modification a day before it was really created.

There, in that brand new file, are those 98 versions going right back to the first 15 months ago, each safely tucked away in the macOS version database. The version files from the first of the two source code files each have creation dates of 8 July 2024, although the Mac mini M4 Pro they are now stored on didn’t exist until that October, and its first macOS was installed on 1 November 2024.

Versatility and Revisionist are both available from their Product Page.

After Dante and Virgil have heard the story of an alchemist who claimed to be able to transform base metals into gold, Dante mentions examples of those who have fallen victim to sudden changes of fate, in Thebes and Troy. But none compares to two of the spirits who sink their teeth into the flesh of others in this tenth rottenpocket. One is named as Gianni Schicchi, a Florentine fraudster who once impersonated a dead man to draw up a false will.

The other is Myrrha, who had incestuous desires for her father so passed herself off as another woman in order to sleep with him. Myrrha was transformed into the tree of that name, and her son was Adonis, the much-admired lover of Venus.

They also see Adam a notorious counterfeiter, Sinon the Greek who persuaded the Trojans to bring the wooden horse into their city, and Potiphar’s wife, who repeatedly tried to seduce Joseph before accusing him of trying to seduce her.

Virgil leads Dante on from the eighth circle of Hell towards the next, for the treacherous. As they approach in fog they hear a deafening horn, and Dante then sees what he thinks are the towers of a distant town; Virgil tells him that they are giants who stand circling the rim of Hell, among them the Titans who waged war against the gods of Olympus.

One of them, Antaeus, takes first Virgil then Dante in his hand to carry them onto Cocytus, the frozen lake forming the ninth circle of Hell.

Here, Dante finds contemporaries who betrayed their kin. Among them are two frozen together almost as one, the Tuscan Sassolo Mascheroni who murdered his cousin for an inheritance, and Camiscion de’ Pazzi who murdered his cousin for property.

Next they meet political traitors, including Bocca degli Abati, a Guelph who aided the opposing Ghibellines. They eventually come across Count Ugolino, who is gnawing the back of the head of Archbishop Ruggieri just like a dog chewing a bone. Their story opens the next article in this series.

The artists

William Blake (1757–1827) was a British visionary painter and illustrator whose last and incomplete work was an illustrated edition of the Divine Comedy for the painter John Linnell. Most of his works shown in this series were created for that, although he did draw and paint scenes during his earlier career. I have a major series on his work here.

William-Adolphe Bouguereau (1825–1905) was a precocious and highly acclaimed academic painter who dominated the Salon in the late nineteenth century with his figurative works, often drawn from mythology. Classically trained at the École des Beaux-Arts, he grew infamous for his nudes painted against false settings, and his vehement opposition to Impressionism. However, he also taught at the Académie Julian, and worked tirelessly even when his paintings fell from favour.

Gustave Doré (1832–1883) was the leading French illustrator of the nineteenth century, whose paintings are still relatively unknown. Early in his career, he produced a complete set of seventy illustrations for translations of the Inferno, first published in 1857 and still being used. These were followed in 1867 by more illustrations for Purgatorio and Paradiso. This article looks at his paintings.

Henry Fuseli (1741–1825) was a Swiss artist (originally Johann Heinrich Füssli) who first came to Britain in 1765, where he worked for much of his life. A successful portraitist and figurative painter, many of his works show the supernatural usually in melodramatic chiaroscuro and were unusual for the time. A professor of painting at the Royal Academy in London, his pupils included John Constable and William Etty, and he was an influence on William Blake. I have two articles about his career and extraordinary work, here and here.

References

Wikipedia
Danteworlds

Robin Kirkpatrick (trans) (2012) Dante, The Divine Comedy, Inferno, Purgatorio, Paradiso, Penguin Classics. ISBN 978 0 141 19749 4.
Richard Lansing (ed) (2000) The Dante Encyclopedia, Routledge. ISBN 978 0 415 87611 7.
Guy P Raffa (2009) The Complete Danteworlds, A Reader’s Guide to the Divine Comedy, Chicago UP. ISBN 978 0 2267 0270 4.
Prue Shaw (2014) Reading Dante, From Here to Eternity, Liveright. ISBN 978 1 63149 006 4.

I hope that you enjoyed Saturday’s Mac Riddles, episode 330. Here are my solutions to them.

1: Sounds like forty to a Roman working with tables to be the best.

2: Four hundred spun up for audio or data.

3: Run as a guest, it could be 995.

The common factor

I look forward to your putting alternative cases.

As I explained a couple of weeks ago, log entries come in four flavours: regular, activity, boundary and signpost. These types have previously been distinguished by a single digit in the entry. Although the latter two aren’t commonly used, boundaries because they’re uncommon, and signposts because they’re seldom useful, activities do need to be distinguished from regular entries. This new build of LogUI uses emoji to do that, and brings improvements in exported entries.

Log list

Rather than display a single digit for the type of each log entry, LogUI now uses an emoji:

1. regular entries are marked with a right-pointing triangle,
2. activities with a softball,
3. boundaries with a clapper board,
4. signposts with a round pushpin.

Those make it much easier to scroll down through entries looking for activities, for example.

Rich Text export

Those are also shown in extracts exported to Rich Text Format files. Those exports have been improved to more closely reflect entries as they’re displayed in LogUI’s window, including the new type emoji, with the addition of extra fields for signposts.

Copy

The other form of exported entries are those copied from the list, by selecting them in the window and using the Copy command. Rather than trying to copy the full text contents of all the fields, this has previously brought a selection separated using tabs. In this version, the fields are expanded and use a vertical bar | as a separator, to provide
date | level | category | sender | process | subsystem | message or signpostName

Where an entry has no data for that field, it’s left empty. As signpost entries don’t have message fields, and the other three types don’t have signpostNames, the last of those depends on the entry type. This should make copied signposts more meaningful.

For example, a short regular entry might provide
2025-10-19 14:48:00.385306+0100 | info | SDNearbyAgentCore | CoreUtils | sharingd | com.apple.sharing | Checking active FT call count: 0
an activity
2025-10-19 14:48:00.902644+0100 | | | RunningBoard | runningboardd | | state update
and a signpost
2025-10-19 14:48:00.435671+0100 | | tracing | SkyLight | WindowServer | com.apple.SkyLight | FrameLifetime

LogUI 1.0 build 77 for macOS 14.6 and later is now available from here: logui177
from Downloads above, and from its Product Page.

Enjoy!

By 1884, Lawrence Alma-Tadema (1836–1912) and his wife Laura (1852–1909) were exhibiting successfully, as well as raising their daughters Anna (1864-1940) and Laurense (1865-1940). Although the younger Laurense went on to become a prolific novelist and poet, Anna was taught to paint by her parents.

Anna was a precocious and brilliant painter in watercolours, and her earliest surviving works, made when she was only seventeen or eighteen, document the interior of the family home near Regent’s Park, London. Sir Lawrence Alma-Tadema’s Library in Townshend House, London (1884) is a meticulously detailed account of that room, even down to the details of its stained glass. That cannot have been this painting’s original title, though, as Anna’s father wasn’t knighted for a further fifteen years.

Anna’s small watercolour of The Drawing Room, Townshend House (1885), painted the following year, shows her improved skills at depicting surface light and texture. This painting was exhibited at the World’s Columbian Exposition in Chicago in 1893, a remarkable achievement for someone who was only eighteen at the time that it was painted.

Lawrence’s A Foregone Conclusion (1885) was commissioned as a wedding gift to the second wife of Sir Henry Tate, founder of the London gallery, Amy Hislop, by Tate himself. It’s one a series on the theme of courtship and marriage: this shows a suitor (left) bringing an engagement ring to his girlfriend ready for his proposal of marriage to her. She hides behind a marble wall with her attendant, their attitude suggesting that his proposal will be successful.

Anna progressed rapidly, and this Self-portrait was one of her early oil paintings, probably dating from around 1887, or slightly later. Its puzzling background is another part of the family home, by then in Saint John’s Wood, to which they moved in 1886. It’s believed that this too was exhibited at the World’s Columbian Exposition in Chicago, in 1893.

Lawrence’s Priestess of Apollo from about 1888 shows one of the priestesses devoted to the god of the sun, who rode the chariot of the sun across the sky each day. He signed this painting in the inscription under the arch, dedicating it to Sir Charles Hallé (1819-1895), the famous conductor who founded the Hallé Orchestra in 1858, and his second wife, the widowed violinist Wilma Neruda; they married in 1888, and this appears to have been another wedding gift.

Spring (1894) is one of Lawrence’s largest and most complex paintings, which took him four years to complete. It shows the spring celebrations in honour of the goddess Flora, the April Florialia.

Hidden in its extravaganza of flowers, marble, pretty girls and young women, are some rather ruder references. The banner at the back of the procession, hung from a balcony, contains verse addressed to Priapus, the god of fertility. This was amplified by attached lines from the contemporary poet Swinburne, which continued by referring to the budding of sexual love in the spring, although those lines remained unquoted here. Finer details on some of the instruments and other objects in the painting show couples frolicking in a state of undress, and there are herms concealed in other parts. The painting was purchased by Robert Mendelssohn-Bartholdy.

A Knock at the Door (1897, Opus 90) is Laura’s most explicit painting in terms of dates. It’s set in 1684, during the period of peace between the Second Treaty of Westminster (1674) and Treaty of Nijmegen (1678), and the crisis in relations with England arising in 1688. We see an attractive young woman, apparently checking that she is looking at her best in a mirror, presumably just before she receives a visitor. On either side there are brief glimpses of open windows.

In 1899, Lawrence was knighted, and in 1900 he was awarded the Grand Prix at the Exposition Universelle in Paris. His second wife Laura died in 1909, and the following year a memorial exhibition of her paintings was held at the Fine Art Society.

Lawrence Alma-Tadema died in 1912, and was buried in Saint Paul’s Cathedral in London, a great mark of honour for any British artist.

Anna continued to exhibit at the Royal Academy until 1928. Following her father’s death, the value of his paintings collapsed, plunging both daughters into poverty. Neither ever married, but Anna continued to make a frugal livelihood from her paintings, which all seem to have vanished.

Reference

Barrow RJ (2001) Lawrence Alma-Tadema, Phaidon Press. ISBN 978 0 7148 4358 2.

The most worrying feature of the current AI ‘revolution’ is how heavily it’s being promoted by everyone from vibe coders to governments. The best and most enduring revolutions are quiet, and bring change because they’re so compelling. If something new has to be heavily evangelised, look deeply inside it to discover why, and who stands to gain most from that snake-oil.

In the case of Mac firmware, change has been so underplayed that you might not have realised what has happened over the last decade. But Macs have gone from impending disaster in Thunderstrike 2 with many running old firmware known to be vulnerable, to Secure Boot and thoroughly reliable updates.

In 2015 Trammell Hudson, Xeno Kovah and Corey Kallenberg demonstrated a firmware worm they named Thunderstrike 2 that could have been abused to insert malware in boot flash storage in Macs. Had that been exploited it would have been disastrous. Apple acted quickly by hiring Kovah and Kallenberg, and a third firmware security researcher Nikolaj Schlej, but shortly after that Rich Smith and Pepijn Bruienne, then of Duo Labs, reported that many Macs were running outdated firmware. When Apple addressed Thunderstrike 2 it could thus have taken a year or more before most Macs would have been protected.

While Kovah, Kallenberg and Schlej were busy securing firmware, and developing eficheck to routinely screen it in every Mac each week, several of us were trying to work out how to maintain a list of current firmware versions for users to check their Macs against. The answer came in eficheck, which obligingly informed us of those it accepted, and we then discovered how to extract firmware update information from macOS updates, for which I’m eternally grateful to Pico for doing the work. From 4 October 2017 those version lists have been published on this blog.

Two years later, in July 2019, firmware version checking was automated in EFIcienC, the precursor to SilentKnight, and became one of the pillars of checking that your Mac was secure.

In my latest revision of that guidance I was at last able to write that firmware “no longer needs to be checked separately” from macOS. My latest list of firmware versions for macOS 26 Tahoe contains just two, compared with over 39 given for High Sierra. The concern of dozens of articles here over those ten years, firmware and its updating can now be trusted, as Macs have moved from EFI to iBridge (T2) and iBoot (Apple silicon), with modern macOS updaters that install firmware reliably. Well, almost every time.

While Apple implies this in its Platform Security Guide, this remains a quiet revolution that didn’t mean anything to marketing, nor was there any mention in a press release. Neither do Apple’s support notes explain how it makes Apple silicon Macs the first to run the firmware matched with their macOS, and to be fully downgradable using IPSW image files.

This journey hasn’t been smooth, and many will still remember models such as the iMac Retina 5K 27-inch Late 2015 (iMac17,1), which in certain configurations simply wouldn’t update its firmware. We discovered that some other Macs updated reliably until their internal storage was replaced. In the end it was the introduction of the T2 chip that made the big difference, bringing the same EFI and iBridge versions across the whole range of Macs.

Compare this with UEFI Secure Boot, an option that Apple wisely decided not to pursue. One recent vulnerability that could have allowed an attacker to deploy malicious bootkits in systems with Secure Boot enabled was reported by ESET in June 2024, but that vulnerable firmware wasn’t revoked by Microsoft until 14 January 2025. Another recent UEFI vulnerability affecting multiple models of Framework computers, BombShell, allows bypass of their Secure Boot, requiring firmware updates that are still being rolled out.

Sometimes we need to look back to see how far we have come.

Painting often runs in the family, as so well illustrated in the Brueghels of Flanders and Brabant. This weekend I look at an artistic family you’re unlikely to have heard of, the Alma-Tademas of London, husband Lawrence, wife Laura, and daughter Anna.

Born as Lourens Alma Tadema in Dronrijp, in the north of the Netherlands, Lawrence (1836–1912) was left to draw and paint following crises in his physical and mental health when he was only 15. By the following year his skills were sufficient for him to enter the Royal Academy of Antwerp, Belgium, where he spent four years. During the later years of that training he worked as a studio assistant to one of the professors at the academy, and became fascinated by Merovingian history.

In 1858-9 he moved to work for Baron Jan August Hendrik Leys, who also acted as his mentor. Leys was an avid painter of mediaeval scenes, who was also a major influence on the early work of the French painter James Tissot.

The Education of the Children of Clovis (also known as The School of Vengeance, or The Training of Clotilde’s Sons) (1861) returns to tales from Merovingian history, showing Saint Clotilde watching her young sons being taught the royal art of axe-throwing. It’s no wonder that later one of them was to murder two of her grandchildren.

In 1862, Alma-Tadema set up his own studio, and the following year he married, honeymooning in Florence, Rome, Naples, and in the excavated ruins of nearby Pompeii.

The year 1869 was a disaster for the Alma-Tadema family. Although Lawrence’s career as a painter had been starting to flourish, his wife Pauline had not been well for a long time, and died suddenly of smallpox. His own health had faltered, but his doctors in Brussels couldn’t agree on a diagnosis. This left him with one option: to go to London to get a second opinion, which he did in December. Once there he was quickly invited to Ford Madox Brown’s house, where he met the two younger Epps girls, then aged nineteen and seventeen.

The oldest of them, Emily (c 1842-1912), was taught by the leading Pre-Raphaelite landscape painter John Brett, and married to become Mrs Emily Williams. The middle daughter, Ellen (1850-1929), was taught by Ford Madox Brown, and married the poet Sir Edmund William Gosse (1849-1928). After their husbands died, Emily and Ellen shared a studio, but neither really achieved fame in their painting.

It was the youngest daughter, born Laura Theresa Epps (1852–1909), with whom Lawrence fell in love at first sight, although he was nearly thirty-four himself. He returned to his family in Brussels, still infatuated with young Laura. Then in July 1870, the Franco-Prussian War broke out, and the whole Alma-Tadema family – Lawrence, his two young daughters, and his sister Atje, who acted as housekeeper – fled to London, where he settled in the September, marrying Laura in July of the following year.

At the age of only nineteen Laura found herself an artist’s wife, step-mother to Laurense and Anna (then seven and four years old), and trying to start her own career as a painter. He quickly became friends with the artists of the Pre-Raphaelite Movement, and his palette brightened. He enjoyed rapid commercial success, and in 1873 Queen Victoria made him an official ‘Denizen’, giving him most of the rights of citizenship.

This is his portrait of The Artist’s Wife when they married.

The Vintage Festival (1871) is one of two similar versions of the same scene, painted using the much brighter and lighter palette that Lawrence developed as he settled in England. It marks the start of his mature style, using classical Greek and Roman themes depicted in intricate detail. These details were researched extensively, sometimes taking as long as two years for a single painting. Following early criticism of his initial attempts to depict the surface properties of marble, he devoted a great deal of effort to painting marble better than any previous artist, so becoming the master of marble.

The meticulous detail in his paintings often gives the impression that these are large canvases and panels, although many are quite small. He was obsessive with what he saw as accuracy, and repeatedly repainted passages until he felt they were perfect.

This painting shows his vision of a Bacchanal being celebrated by musical Bacchantes in a private villa. Its tame nature may surprise those accustomed to thinking of such festivals as rampage, but gives scope for fine details such as the leather straps on the faces of those playing wind instruments. It also has a strong sense of Aestheticism, with its evocation of sound and music, as well as the heady aromas from burning incense.

Despite her new and demanding roles, Laura was quick to achieve recognition in her painting. Her first work to be exhibited at the Salon in Paris was in 1873, and that same year she started exhibiting at the Royal Academy in London. I don’t know if her early painting The Tea Party (date not known, Opus 7) was one of those, but I believe it shows her step-daughter Laurense playing with her dolls.

Lawrence was also a skilled painter of portraits; his most touching, though, must be This is Our Corner (1873), a double portrait of his daughters Anna (1864-1940) in front, and Laurense (1865-1940) behind. They both remained unmarried through adult life: Anna became an accomplished artist, and Laurense a prolific novelist and poet.

Sunny Days (1874) may come as a surprise to those who know Lawrence for his Salon-style works, but during the 1870s he started painting small landscapes, typically of his family when they were on holiday. This shows his daughter Anna in what could be seen as the closest that he came to Impressionism, and was perhaps modelled after one of Monet’s paintings of the time. On this occasion, the landscape is only in Surrey, but he also painted these when in mainland Europe.

Laura’s World of Dreams from 1876 introduces a theme that she was to develop in her mature works: the reflection and transmission of images in mirrors and windows, adding depth to what would otherwise be a shallow view. Here a nurse/nanny (or possibly mother) has fallen asleep, exhausted, on a large illustrated family Bible, which is open at the start of the book of Amos.

Laura was one of only two British women artists to have work accepted for the Exposition Universelle in Paris in 1878.

A Looking out o’Window, Sunshine (?1881, Opus 81) is by far the most outstanding of Laura’s paintings that I have found, with its captivating portrayal of childhood, radiant lightness, and its play of reflections on the glass of the window. It’s also composed to reverse the normal balance in brightness between indoors and out: in reality, of course, outdoor light levels would have been much greater than those indoors, but Laura has managed to ‘cheat’ that by her choice of light colours in the interior wood, clothing, and chair.

Reference

Barrow RJ (2001) Lawrence Alma-Tadema, Phaidon Press. ISBN 978 0 7148 4358 2.

Here are this weekend’s Mac riddles to entertain you through family time, shopping and recreation.

1: Sounds like forty to a Roman working with tables to be the best.

2: Four hundred spun up for audio or data.

3: Run as a guest, it could be 995.

To help you cross-check your solutions, or confuse you further, there’s a common factor between them.

I’ll post my solutions first thing on Monday morning.

Please don’t post your solutions as comments here: it spoils it for others.