Does anyone have any knowledge about ColorSync, a built-in macOS app?
Why am I asking? I'm trying to get rid of eyestrain on iMac. Yesterday I found an interesting idea. Please see the video: https://www.youtube.com/watch?v=YwjLuUR51gE
And here is the link to the website of this solution's author: https://www.sebastianleitner.com Full description is under e-books tab. I'll give some extracts below.
This guy says that if ColorSync gets involved in color management, there happens the following:
If you go into Display Preferences (in your system preferences) and change the tab to "color" you will see you can choose from a bunch of ICC profiles, which are all basically LUTs for your graphics card. Don't play around with it too much but definitely disable "True Tone" on latest Mac models. By default your Mac uses one that matches your screen Apple put in and optimized. BUT ColorSync is working its "magic" in the background and screwing with the otherwise well calibrated levels to transform any signal to P3. While not every display can natively display P3, it can certainly run rec709 or sRGB which will both look a lot punchier/contrasty and that's the way it should be on such high-performance LED screens.
One solution (a rather pricey one) would be having a professional calibrate your system and screen so you can actually see the right color/gamma values depending on your environment without the system interfering. Another, free and quick, solution is below.
The quickest, free solution is easy but kind of secret and not well documented at all! You need a display profile that circumvents ColorSync, tricking your system into displaying raw values only without transforming them! And the only profile (provided by Apple in 2012 by the way) to do so is called HD 709-A. Some people don't have it for some reason even though it's by Apple, so you can download it below (and put it in "User/Library/Color Sync/Profiles")! It will take care of this tedious issue once and for all. In my experience, color and gamma are consistent across all kinds of different systems and hardware setups – yes, even broadcast monitoring/referencing setups. NOT cinema obviously, since the color standard there is DCI P3 in XYZ levels – not RGB (this is how all digital displays work).
And indeed, HD 709-A is in the list of Display color profiles under System Preferences ＞ Display ﹥ Color, but not in the list of ColorSync ＞ Profiles ＞ System.
He is using it to force different apps, namely video players, show the same colors.
But my questions are: How can ColorSync distort colors? (if it can) Could it be connected with the eyestrain? (I have a better experience with a so called "color managed" Safari than with other programs, that's why I'm digging in this direction. Could the display calibration make the Mac screen more bearable?
I'm now testing this HD 709-A profile, but as it makes colors too saturated on iMac, I've made some changes with Gamma Control (decreasing not only the white color luminance, but also the Red/Green/Blue sliders in White and Grey tabs).