Many of the great Masters are known to have painted preparatory studies prior to starting on full-size finished studio paintings. Unfortunately, most of those studies were either destroyed by the artist in their lifetime, or by their heirs following their death. Seeing studies alongside a finished work tells a great deal about the artist’s intent and methods, and some exhibitions have made a point of including as many studies as possible. This article shows a small selection of some whose images I have been able to gather.

Some of the best surviving studies are the oil sketches made by Peter Paul Rubens, some of which were given to assistants in his studio for completion.

Towards the end of his life, he painted this brilliant oil sketch of The Rape of Hippodame (c 1637-38). At the right, Eurytus is trying to carry off Hippodame, the bride, with Theseus just about to rescue her from the centaur’s back. At the left, Lapiths are attacking with their weapons, and behind them another centaur is trying to abduct a woman. Rubens typically sketched on small wood panels, here 26 x 40 cm (10 x 16 inches), with wonderfully painterly brushstrokes.

That became this finished painting, The Rape of Hippodame (Lapiths and Centaurs) (1636-38), which remains faithful to the sketch and its composition. Facial expressions, particularly that of the Lapith at the left bearing a sword, are particularly powerful.

Studies were better preserved in the nineteenth century, when tastes changed and some realised worthwhile sums in posthumous sales of the contents of studios.

Among the most studied are those made by Géricault when he was working up his landmark painting of The Raft of the Medusa. This oil study on canvas was probably made as he was completing his preparations during the autumn of 1818, and reveals some of his compositional thinking, for instance over the size of the ship that rescued the survivors.

The end result is this vast canvas, its figures shown life-sized, which has had huge impact on everyone who has seen it since its completion in 1819. It appears completely authentic, and given the work that Géricault put into making it so, that’s perhaps not surprising. But most gain the impression that the raft was almost square in form, as a result of the tight cropping applied, and that even with those few survivors on board, it was overcrowded. This is because Géricault chose to pack all his figures into one small section of the raft.

I was fortunate enough to visit an exhibition of some of John Constable’s works, in which his studies were shown alongside finished paintings. Here I show just one example. Had Constable lived fifty years later, he might have been persuaded to stop his paintings when they were still late oil studies, rather than take them to their finished conclusions.

This early sketch of Hadleigh Castle (1828-29) already contains some surprisingly detailed passages: at the far left, a shepherd, his black dog by his side, with a small flock of sheep grazing near the ruined tower. There’s a brown and white blob on the seaward slope, probably a cow grazing there. Wheeling in wrinkles of impasto above the tower are a few birds resembling small runnels of liquid metal like solder. By this time, many artists were painting their oil studies on cheaper millboard, as Constable did here. Millboard is made by pasting together many sheets of fine paper, so isn’t as durable as cheaper stretched canvas.

By the finished work, the splendid Hadleigh Castle, The Mouth of the Thames – Morning after a Stormy Night (1829), the basic disposition of those figures has changed little, but Constable has changed each to suit his image. The shepherd, still carrying his long crook, is separated from his dog, and has lost his sheep, which have become scattered rocks. The single cow on the sloping grass has gained a couple of friends, and a cowherd. Beyond them are another couple of tiny specks of figures, and there are more by the wood in the lower right corner.

William Powell Frith’s late study for Derby Day was probably painted in about 1856, and is very close to the finished work shown below, although covering only about a tenth of its area.

Jacob Bell commissioned Frith to paint his finished Derby Day (1856-58) for the huge fee of £1,500, and the artist was paid a further £1,500 for rights to make prints. It was exhibited at the Royal Academy in 1858, and proved so popular that a guard rail had to be installed in front of it to protect the work from the admiring crowds.

Georges Seurat’s preparations are also revealed in his surviving studies, and are very different given his Pointillist technique. Some of the later Divisionists made conventional studies, and there are some experimental examples using larger tiles of colour (see below). Seurat instead rehearsed parts of the overall view when preparing his masterwork.

Seurat’s first and greatest masterpiece, generally known as La Grande Jatte, uses the technique of optical mixing of colour. Rather than blending pigments on the canvas, it’s constructed of tiny dots that are high in chroma, and allow for optical mixing, one of the fundamental techniques in Seurat’s new scientific painting. His theory was that the mixing of colour would then occur in the retina of the viewer, and he tried this in a pure landscape study (above), and in his huge finished painting (below).

He painted his finished version in three phases. In the first, the dots he applied were mixed from available and fairly conventional pigments, including duller earths. In the second phase, he used a limited number of brighter and higher chroma pigments. In the third and final phase he added coloured borders which are distinctive of his paintings.

By the late nineteenth century oil studies were being supplemented by photographs.

Thomas Eakins’ preparatory studies for Swimming (1885) grew from a series of photographs taken by the artist and his friends. But photos never replaced his own sketches: for this work, Eakins made several figure studies, details such as the dog, and different landscape backgrounds, then brought them together in oil sketches.

Once he was happy, he embarked on his final version. In at least some cases, including his paintings of shad fishing from 1881-82, the figures in his Arcadia (c 1883), and Swimming (1885), he put final photographic images into a ‘magic lantern’ projector, which he then projected at the canvas.

He developed a sophisticated system not only for using the projected image to make a graphite underdrawing, but as the painting progressed, to incise key points and lines of reference in the paint surface. This enabled him to create paintings that were accurately calibrated to his reference images: a great advance on the traditional system of enlargement using grids, and one factor in his detailed realism. This technique was discovered by Mark Tucker and Nica Gutman.

Together with other photos and various studies, Eakins then painted Swimming (The Swimming Hole) in 1885.

Albert Bierstadt was more traditional in his preparatory studies for The Last of the Buffalo in 1888.

This late study was painted on canvas, and is 63 x 91 cm (25 x 36 inches). It concentrates on the action to be embedded in a broader landscape.

Bierstadt’s finished painting is larger still, and sets that action in a more characteristic grand panorama, with bleached skulls and dying buffalo in the foreground. In the middle distance are hundreds of animals in the herd, suggesting that extinction was by no means the only outcome.

Finally, a pair of paintings by the less-known Divisionist Henri-Edmond Cross shows an alternative approach to Seurat’s, where his study is built of small daubs of colour, which are then reduced in size for the Pointillism of his final version.

His Clearing in Provence from about 1906 was painted on paper, and has subsequently been mounted on canvas for display in the Israel Museum, Jerusalem.

That sketch formed the basis of the woodland setting Cross used in The Glade, painted in oils in 1906. Colour changes are prominent, and the chroma has been considerably enhanced. The size has grown, and it’s on a more permanent support of stretched canvas.

Seen through modern eyes, many of the oil studies of the past deserve to be seen more widely, rather than being kept in storage.

As landscape painters increasingly came to rely on studies made in front of the motif, and their views came closer to reality, faithful depictions of reflections on water increased. But the fundamental challenges of painting accurate reflections remained. Both John Constable and JMW Turner started their careers drawing, trained in the Royal Academy Schools, and should have had a thorough grounding in 3D projection and reflections, as well as ample experience recording what they saw.

Several of Constable’s major works include reflected passages, painted slowly in the studio following extensive studies made of the motif.

Constable’s commissioned painting of the house and estate at Wivenhoe Park, Essex from 1816 is an oddly distant view of Major-General Francis Slater-Rebow’s country seat. Given the expanse of mirror-like lake, he might have been expected to include meticulous reflections. There are obvious anomalies, such as the brick-red reflection of the modest section of the house visible through a break in the trees in the centre of the canvas. The house is sufficiently distant that little or none of it would have been visible in reflection, let alone the two large areas of brick red stretching well over half way across the water. That was in all probability painted for effect.

Reflections of the pair of swans and boatmen are also out of kilter. Constable may well have neither seen nor sketched them from life, and then struggled to envision their reflections in the studio.

Four years later, this painting of Dedham Lock and Mill (1820) is more familiar territory from the artist’s home ground. His family owned this lock on the River Stour, and he would have worshipped in the village church of Dedham seen in the distance. His reflections here appear accurate throughout.

Turner’s approach to reflections changed over the course of his career. In Pope’s Villa, at Twickenham from 1808, he depicted complex and intricate reflections in careful detail.

I’ve previously considered the relatively small anomalies in another of his early oil paintings, Crossing the Brook from 1815.

These could be accounted for by the figures being staffage added in the studio without the benefit of plein air studies.

Some of his later watercolours, such as Norham Castle, on the River Tweed (1823), have obvious quirks in their reflections: here the reflection appears to show another high point at the left edge of the castle that isn’t matched by an equivalent high point in the real castle.

Some of his paintings show other optical oddities. His Bridge of Sighs, Ducal Palace and Custom-House, Venice: Canaletti Painting (1833), his first oil painting of Venice, places all the buildings leaning to the left, with their reflections leaning in the opposite direction. Had this painting been on a canvas support, there might have been distortion applied by its stretching or subsequent treatment, but unusually Turner painted this on a mahogany panel. I have checked this image matches those from other sources, to ensure this isn’t a photographic artefact.

Turner’s famous Fighting Temeraire from 1839 breaks most of the optical rules of reflections, most obviously in the extraordinary reflected image of the tug’s prow. The tip of the bowsprit isn’t vertically aligned between original and reflection, and there’s gross vertical exaggeration, as there is in the ghostly reflection of the Temeraire under tow.

Several of Turner’s later paintings appear founded in sound optical principles, then exaggerated for artistic effect. While many of the reflections in his Campo Santo, Venice from 1842 appear faithful, he has grossly exaggerated the vertical axis of the reflections of the white sails to the left of centre. But the effect is wonderful.

The Dogano, San Giorgio, Citella, from the Steps of the Europa, from the same year, takes a few gentle liberties with optics without becoming too obviously inaccurate. Again this is mainly in vertical scaling, and Turner has been careful to ensure good vertical alignment throughout.

I have already pointed out some of the apparently deliberate optical anomalies seen in the reflections in Turner’s late oil painting War. The Exile and the Rock Limpet (1842).

Given Turner’s experience and record, I don’t think those discrepancies are errors, but are devices he has successfully used for their effect.

Following the early death of Thomas Girtin in 1802, there was no successor who proved as prolific in painting the cathedrals of Britain, and attention was transferred to those further south.

In 1894, Benjamin Williams Leader painted this view of Worcester Cathedral backing onto the River Severn. This was built between 1084-1504 in an unusual mixture of styles from Norman to Perpendicular Gothic, and contains the tomb of King John in its chancel. Judging by the smoke rising from the chimneys, this was painted in the early autumn.

If any artist came close to Girtin’s achievement it must have been John Constable. In about 1820, Bishop John Fisher commissioned him to paint Salisbury Cathedral from the grounds of his Palace, and Constable started to prepare sketches and studies for that medium-sized painting Salisbury Cathedral from the Bishop’s Garden, completed in 1823.

Constable was still battling with depression after the death of his wife when Archdeacon John Fisher, younger cousin of the Bishop, who had died in 1825, encouraged him to paint a larger and more ambitious view of Salisbury Cathedral, from the nearby meadows on the banks of the River Nadder. This late oil sketch was sold by auction in 2015 for more than five million dollars.

Constable completed his finished painting above for exhibition in the Royal Academy in 1831. It is perhaps a little over-egged with its storm clouds, rainbow and bolt of lightning. Despite several showings, it remained unsold when Constable died. Salisbury Cathedral was almost entirely built within the period 1220-1258, although its tower and spire, the tallest in England, were completed by 1330.

Although there is a Westminster Cathedral in London, it’s Roman Catholic, unlike the more famous Westminster Abbey, a collegiate church of the Church of England that has long been popular for coronations and interments of British monarchs and the nation’s most distinguished figures. The present building was constructed between 1245-1269 close to the Palace of Westminster on the north bank of the River Thames.

Samuel Scott’s Westminster from Lambeth, with the Ceremonial Barge of the Ironmongers’ Company (c 1745) shows a section of the River Thames on a windy day, with showers not far away. Teams of rowers pull their boats out to attend to the ceremonial barges in the foreground, reminiscent of Venetian boat ceremonies. The opposite bank shows, from the left, the imposing twin towers of Westminster Abbey, the old Palace of Westminster almost hidden behind trees, and Westminster Bridge.

The American history painter Benjamin West painted this view of Milkmaids in St. James’s Park, Westminster Abbey beyond in about 1801. Two cows and attendant milkmaids are providing a supply of fresh milk for the crowds in this royal park with Buckingham Palace on its edge. This remains 57 acres (23 hectares) of grass, trees and lakes.

The Church of England cathedral in London is of course Saint Paul’s, on Ludgate Hill a few miles to the east in the centre of the city of London. It was built between 1675-1710 to the designs of Sir Christopher Wren, following the destruction of its predecessor in the Great Fire of London of 1666.

Canaletto painted this imposing view of St. Paul’s Cathedral when he was working in England in about 1754. This Venetian artist lived and painted in London between 1746-1755 when the War of the Austrian Succession disrupted the art market in Venice.

Nicholas Chevalier painted ‘Thanksgiving Day’: The Procession to St Paul’s Cathedral, 27 February 1872 shortly after this royal event. Not to be confused with US Thanksgiving, this was a one-off state thanksgiving for the recovery from severe illness of the Prince of Wales. The widowed Queen Victoria and her son Prince Edward attended Saint Paul’s Cathedral (the obvious dome in the distance) to give public thanks to God. Approaching the arch is the carriage containing the royal party.

Canaletto wasn’t the only visitor from continental Europe to paint Wren’s prominent dome.

From 1880, Jules Bastien-Lepage visited London repeatedly. Blackfriars Bridge and the Thames, London (1881) is his fine depiction of this stretch of the River Thames, with his characteristic gradation of detail from its foreground into the distance. Standing proud on the skyline towards the right is the distinctive dome of Saint Paul’s.

Henri Le Sidaner also visited Britain on several occasions, and in 1906-07 painted this view of St. Paul’s from the River: Morning Sun in Winter, which may have been inspired by Monet’s series paintings of Rouen Cathedral, here expressed using his own distinctive marks.

In case you think Wren’s Saint Paul’s appears recent compared with Britain’s older cathedrals, in my lifetime I have seen two new Church of England cathedrals consecrated: Coventry in 1962, replacing an older building destroyed during the Second World War, and Guildford in 1961, built on a new site altogether over a period of twenty-five years.

As in other countries across Europe at the time, industry in the Dutch Republic during the Golden Age was largely dependent on wind and water, forces that were seldom in short supply. Here’s a small selection of what were effectively some of the first paintings of industry long before the industrial revolution.

Both watermills and windmills date back to ancient times, and became widespread in the Middle Ages. By the seventeenth century they were used for grinding grain into flour, processing wool and fabrics, sharpening tools, forging and metalcraft, manufacturing paper, sawing timber, and sundry other purposes.

Jacob van Ruisdael’s Two Watermills and an Open Sluice from 1653 is not just a superb landscape painting, but a clear technical account of one of the commonest types of watermill.

Since the Middle Ages in Europe, by far the most common type of waterwheel stands vertically, turning a horizontal axle. The terrain here is fairly flat, so the water supplying the mill comes from only slightly above the level of the outlet. Therefore, the mill is undershot, with only the lowest part of each waterwheel getting wet at any moment. To the right of the twin waterwheels is a sluice gate and overflow to control the level of water in the millpond upstream. Additional sluice gates set upstream of the two wheels give fine control over the water flowing through the mill race or leat, and can be used to stop the wheels from turning when the mill isn’t in use.

Van Ruisdael’s Landscape with a Watermill and Men Cutting Reeds from about the same year shows a smaller and simpler mill which is also undershot. Although the mill buildings may appear dilapidated, the gear appears better maintained and still in everyday use. There’s even a figure at the door of the millhouse.

In another painting from about the same time, van Ruisdael’s Landscape with a Mill-run and Ruins shows what had once been a substantial watermill in an advanced state of decay. The extensive brickwork was used to channel the mill race.

Van Ruisdael’s enthusiasm for painting watermills was passed on to his successor Meindert Hobbema. His Wooded Landscape with a Watermill from 1663 shows another undershot mill in similarly flat and wooded terrain. Hobbema used more staffage than van Ruisdael, though, as shown here in the couple and livestock.

Van Ruisdael’s watermills are desolate, devoid of people, but Hobbema’s magnificent Watermill from about 1664 accommodates a family: the wife is out doing the washing in a barrel, while the husband and son walk through their garden. It’s also relatively unusual in that the water here is fed through the elevated wooden aqueducts, making this watermill overshot. This could develop more power with a lower flow of water, because it uses the weight of water falling against the blades of the waterwheel rather than just its flow.

The Republic was famous for its numerous windmills, that were almost universally vertical in design, with their sails rotating in a vertical plane. Other parts of Europe, mainly the south and east, often preferred horizontal designs that look very different.

I can count half a dozen windmills clustered around the port of Dordrecht in Jan van Goyen’s View of Dordrecht with the Grote Kirk Across the Maas from 1644.

Rembrandt painted few non-narrative landscapes, but among them is this dramatic view of The Mill (1645-48) seen in the rich rays of twilight. This is a classical post mill set on top of a roundhouse, where the whole of the wooden mill structure is built around a central post, and is turned to face into the wind.

The great masters of Dutch landscape art like Jacob van Ruisdael must have painted many hundreds of windmills, of which one of the best-known is this view of The Windmill at Wijk bij Duurstede from about 1670. This is a more substantial tower mill, where only the cap at the top rotated to catch the wind. This small town, now a city, is on the bank of the River Rhine, an ideal location for delivering grain by barge, and shipping the resulting flour. This should have kept the mill as busy as the wind allowed, and its owner prosperous.

Golden Age paintings of windmills became so well-known that later artists copied them.

This view of a Landscape with Windmills near Haarlem was painted by John Constable in 1830, almost two centuries after the original by Jacob van Ruisdael.

Watermills and windmills remained in widespread use in the Netherlands until the latter half of the nineteenth century, when they were largely replaced by steam power, fuelled by coal imported from the mining areas of Belgium and north-eastern France, and Britain. It wasn’t until the twentieth century that wind turbines started to make use of the forces of nature again.