Working with older colour displays, particularly bulky and heavy CRT models, wasn’t easy. Colour calibration was all-important if you wanted what you saw on screen to look anything like what appeared from the printer. Apple’s newer displays, including the Studio, Pro Display XDR, and the high-end XDR screens in MacBook Pro models, are intended to be much less demanding in use while still producing faithful colour. Unless you’re a professional colour-grading video or achieving perfection in your photos, you should never need to calibrate these displays. This article explains how this works, and how you can tweak those displays to your own liking.

As I explained in my brief history of ColorSync last weekend, each device including displays has a limited range of colours it can reproduce, its gamut. To ensure consistency in the use of colour throughout macOS, each device has its own colour profile that’s used by ColorSync, the colour management system. In the past, those who cared about colour used a colour measurement device for display calibration, the production of a colour profile for ColorSync. For CRT displays this could be a lengthy procedure, as the display had to warm up fully before calibration could start, and the procedure had to be repeated periodically to ensure the profile matched the display as it aged.

Apple Studio, Apple Pro Display XDR, and MacBook Pro XDR internal displays are intended to have stable and standard calibrations over long periods. For example, the Studio display incorporates an A13 Bionic iPhone chip running a cut-down version of iOS 17 that is most likely involved. These displays are manufactured to meet a standard calibration supplied as a preset in macOS. The only option for display recalibration is to a ‘factory’ standard using high-end instruments, thus not something for most users to attempt. All you can do is tweak the presets provided, perhaps with the aid of a colorimeter to measure white point and luminance.

Presets are accessed in Displays settings, and include the master, named Apple Display (P3-600 nits), Apple XDR Display (P3-1600 nits) or similar. Below that is a list of variants for specific purposes. If you were to select Calibrate Display… at this point, all you could do would be to perform a full ‘factory’ calibration if you happened to have the right instruments to hand.

Instead, select the Customise Presets… command.

With the master preset selected, clicking the + tool to add a custom preset will create a copy of that, where you can mix your own preset. For this you can select:

• a colour gamut, default P3, with options including sRGB, PAL and NTSC;
• a white point, default D65, with options including D50, DCI and custom;
• an SDR transfer function, default Pure Power, with options of sRGB and others;
• whether to boost the system gamma;
• a maximum luminance, defaulting to 600 for SDR or 1,600 nits for HDR;
• whether to limit luminance to that achievable over the whole display.

When a custom preset (not the master) is selected, the Calibrate Display… menu command should offer you two fine-tune options as well as a full calibration.

Fine-Tune Calibration is intended for use with a colorimeter or other instrument that can measure white point and luminance.

You can then enter the measured values and those that you want from the display, through this fine-tuning.

The other option is to perform a Visual Fine-Tune, for which no measuring instrument is used.

All this does is allow you to select a custom white point from this matrix of colours.

For the great majority of users, those should be all you need to achieve faithful reproduction of colour on your display. If you feel that you need to be able to do more, then you’d probably be better looking at Eizo ColorEdge or similar products that offer more traditional calibration.

Yesterday’s brief history of ColorSync was one of the most interesting in this series to research. In most cases, these brief histories cover well-trodden ground, with several previous accounts to provide a framework for my collection of screenshots and personal experience. On this occasion, even Wikipedia was vague and brief. Yet at the time ColorSync’s role was of great importance, as faithful colour reproduction was so essential to the creatives and businesses that relied on Macs.

It’s also a richly multi-disciplinary field, drawing on neurophysiology, physics, colour science and perceptual psychology. Key concepts like the modelling of colour appearance have grown into lengthy and highly technical books, several of which I seem to have collected over the years. They also provide absorbing accounts of the lengthy journey over several centuries to bring basics such as colour order systems.

In 1615, the Flemish physicist Franciscus Aguilonius, also known as François d’Aguilon, (1567-1617) was the first to propose a colour line extending from white (albus) to black (niger), passing through the primaries of yellow (flavus), red (rubeus), and blue (caeruleus). Below that are secondary combinations of orange (aureus) and purple (purpureus), with green (viridis). This was published in his six volume treatise on optics, whose title page and illustrations were designed by Peter Paul Rubens.

In the early twentieth century, Albert Henry Munsell (1858-1918) devised a system closer to those used to specify colour today. This shows the circle of ten hues, here displayed with values of 5 and chromas of 6. The vertical value scale ranging from 0 to 10 is shown in neutral colours, from black to white. A wedge of constant 5PB hue is then shown at a fixed value of 5, the chromas ranging from 0 (grey) to 12 (pure colour).

Contemporary designers are also familiar with the Pantone System of swatches of standardised colours, that have become standards in several sectors such as process colour printing.

The problem tackled by ColorSync is that no device used with computers can represent the full range of colours, each having its own range or gamut. For colour to appear consistent in the image captured by a scanner or camera, on the display used to adjust settings such as white point and balance, and in the final printed page, colours have to be adjusted or mapped to look right on that device. To do that each device has its own colour profile, and a colour management system adjusts colours on each according to the desired quality and goals of the operator.

Most of the principles involved were known before the arrival of Macs. But when Apple, Adobe, Agfa, Microsoft, Kodak, Silicon Graphics, Sun and Taligent (an Apple-IBM partnership) sat down together in 1993 as the International Colour Consortium, they had a lot of work to do before photographers and designers could have confidence that their work would survive the journey into print retaining what appeared to be faithful colour.

ColorSync and colour management is but one example of the broad range of fields that form the basis of what we do on our Macs, from floating point computation to Unicode text. With the marketing drive to sell modern computers as appliances, we have lost sight of what goes into them. Just as with transport history, our view of what happened is largely superficial and limited to the tangible in collections of hardware.

This misleads us into thinking that today’s Artificial Intelligence is somehow capable of replacing human research and discovery when all it can really do is rehash what we have created in the past. If any of today’s much-vaunted large language models could have started to tackle the problems addressed by ColorSync during the 1990s, do you seriously think that they would have come up with the solutions embedded in Mac OS X less than a decade later? For without prior knowledge won by humans, we’d still be wrestling with the number of rs in the word strawberry.

Let’s celebrate human achievement and empower that instead.

Each colour output device, such as a printer, has a limited range of colours that it can reproduce, its gamut. To ensure that output best matches expectations, it’s necessary to adjust colours to a device colour profile using a colour management system. When Apple released the Macintosh II in 1987, colour management was in its infancy. With the development of colour output devices like inkjet printers, Xerox, Apple and other manufacturers realised its importance. Apple therefore recruited Robin D. Myers and together with Gary Starkweather they started work on what was to become the first version of ColorSync, released in January 1993.

That year Apple, Adobe, Microsoft, Kodak and others co-founded the International Color Consortium (ICC) to develop ColorSync into an open cross-platform colour management system, and worked on improvements to version 1.0. Although ColorSync was being integrated more with the Mac System, its use remained optional until the release of Mac OS X, and until then plenty of software simply ignored it.

ColorSync 1.2 brought support for Apple’s new PowerPC-based Macs, then in March 1995 ColorSync 2.0 brought major improvements, and was followed by 2.5, probably released with System 7.6.1 in 1997.

ColorSync is seen here in the later days of Classic Mac OS in 2001, managing colour profiles for devices, and providing colour management workflows.

ColorSync 2.0 used a new format for device profiles that had been developed by the ICC for use over a wide range of platforms and devices, although it retained backward compatibility with version 1.0 profiles. In addition to supporting input devices (scanners, cameras), displays, and output devices (printers), these new profiles also supported device links for batch processing, colour space conversions, and abstract devices for subjective transformations. Embedded profiles contained additional information indicating desired quality and rendering intent for colour matching. Printing to a ColorSync-aware printer driver became transparent for apps, allowing them to get the most from the built-in colour management in Mac OS.

With the release of Mac OS X 10.0 Cheetah in 2001, ColorSync came of age and was fully integrated at last, and had won its place in System Prefs. Version 4.0 was soon released in Mac OS X 10.1 Puma that September.

ColorSync Utility provided a rich range of tools for managing device profiles, and repairing any that had become damaged.

The following sequence of screenshots shows the calibration of an Apple Studio Display using Display Calibrator in Mac OS X 10.2 Jaguar in 2003.

ColorSync Utility’s features continued to grow, with the addition of a colour calculator in Mac OS X 10.4 Tiger, and improved visualisation of profiles, seen here in Mac OS X 10.5 Leopard in May 2009.

Colour profiles for printers were often specific not just to the printer, but also to the type of paper used, as with these in Mac OS X 10.7 Lion in 2011.

Since then, the demand for quality colour printing has steadily declined, and by macOS Monterey in 2021, ColorSync Utility was growing neglected, and its Calculator was and remains dysfunctional. The Display Calibrator app is now buried deep in /System/Library/ColorSync/Calibrators. A new colour calibration tool, Pro Display Calibrator, is tucked away in /System/Library/CoreServices to support Apple’s Pro Display XDR, but little has been done to develop the capabilities of the Studio Display since its introduction in 2022.

ColorSync version 4.13.0 carries on managing colour in macOS Sequoia 15, an unsung triumph of science and engineering.

References

Robin D. Myers’ early history
David Hayward Print Hints: Syncing Up With ColorSync 2.0, develop issue 23, September 1995
Apple, ColorSync on Mac OS X, Technical Note TN2035, 8 October 2005
Alas ColorSync Utility!