Dear ColorSync specialists, I want to recheck with you is my understanding of ColorSync displays principals is correct. Is it correct that for any desktop window in the macOS ColorSync make next color transformation: - transform RGB to XYZ via "Generic RGB profile.icc" with relative colorimetric intent - transform XYZ to RGB' via display profile with the intent from profile header (display that contain most part of window) - show RGB' - Additionally VCGT tag used to apply graphics-board LUT And all that transformations made without using chad (chromatic adaptation). Please point me if there is something wrong in this statements. And maybe i missed something. Also I'm interested to hear ColorSync developers what is their expectations to displays profile. Is display profiles can be used only for display matching in macOS? Or there is correct combination of accurate profile and vcgt that can describe and calibrate display in same time? The problem that i see here is next. If I have profile built by the display measurements and then add vcgt tag to change color or gamma of the display, then profile is not describing current display state anymore. In such case i feel that color-managed software can't rely on such profile anymore. With opposite approach we also have a problem: If I build profile with the applied vcgt to have accurate display profile and then apply it to the display, then macOS use it to match colors to generic rgb. So vcgt calibration lost in result. Maybe you have some described recipes how to create correct display ICC profile that change display gamma and in same type describe new state. One more question. Is it possible to end-user and to developers to change main color space (Generic RGB be default)? And why was Generic RGB chosen, not Apple RGB for example? Any help very appreciated. Thank you. Best regards, Vitaly Bondar