Hi Andrew. Thanks for the reply. [regards RGB values staying the same when converting between Gray Gamma 2.2 <-> Adobe RGB (1998) ] <snip> With the gamma alone, why would you expect the values to remain the same? Two reasons. 1: RGB pixel values stay the same when doing conversions from Gray Gamma 2.2 <-> Adobe RGB (1998) in Photoshop 2019. 2: My understanding is that the Gray axis of Adobe RGB (1998) and the 'Gray axis' of Gamma 2.2 space are identical. Values 0 to 255 encoded Gamma 2.2. So the color meaning of RGB values along the gray axis of Adobe RGB (1998), and the color meaning for the same 'RGB' value in gray gamma 2.2 space are also identical. So that's a null conversion between them. And that expectation is being meet with the behavior of Photoshop 2019. It does not change the RGB values for gray, when converting in either direction between Adobe 1998 <-> Gray Gamma 2.2. But Photoshop 2022 does (on my install). Silent Changes of RGB values in PS 2022: This gets more interesting. I created a patches in PS 2019 in Gray Gamma 2.2 space. The RGB patch values were 0, 5, 10, 15, 20. I then saved it with Gray Gamma 2.2 embedded. I opened the very same file in PS 2022. The eye dropper in PS 2022 indicates that the RGB values have silently been changed (without any pop-up warnings) to 0,1,3, 6,12. Yet the L* meaning of those new numbers did not change. (all profile mis-match warnings are on.) Implied Gray Gamma 2.2 implementation Change in PS2022: The eyedropper is indicating that PS 2022 has silently changed the RGB values in my PS 2019 Gray Gamma 2.2 file. But the L* meaning of the pixels is being preserved. But two files having the same colour meaning, while using different RGB pixel values to achieve them mean that the two images are not encoded in the same colour space. If the RGB numbers in PS 2022 are to believed, that would mean that Gray Gamma 2.2 in PS 2019 is not the same as Gray Gamma 2.2 in PS 2022. Either that, or the eyedropper RGB Pixel read-out values in PS 2022 are just plain wrong. (For Gray Gamma 2.2 space.) Other PS 2022 odd behavior 2: Make a solid black canvas (0,0,0) in Gray Gamma 2.2 in PS 2022. 8 bit. Put a levels adjustment layer above it. Place an eye dropper and set it to display RGB values, to monitor changes made from the Levels layer. Slide the Levels output Black-Point slider up one step at a time to make the black image lighter. In PS 2022 I need to move the Levels output slider to '5' before the image even begins to indicate a change. And even then it only changes to RGB 1,1,1. In PS 2019 if I do the same thing and move the Levels output black-point slider up, The full black RGB values lift in lock-step to the Levels output slider value. At slider value 5, the image Black is lifted to '5,5,5'. But not in PS 2022. Other PS 2022 odd behavior 3: Make a new canvas, Gray Gamma 2.2 image in PS 2022. In 'Tools' pallet change the foreground pallet color. Type 15, 15, 15 into the RGB settings. Flood the canvas with this color. Place an eye dropper in the canvas and change the display to show RGB values. My eyedropper says the canvas is flooded with 14,14,14. Any one else getting this sort of behavior with Photoshop 2022? Thanks Peter Miles