On Aug 15, 2019, at 9:14 AM, David Miller via colorsync-users <colorsync-users@lists.apple.com> wrote:
There’s definitely something wrong here in 10.14.6, and you don’t even need to use a display profile to see it.
Set the display profile to Adobe RGB. It uses the TRC tags with the “curv” type and simple gamma value. It also doesn’t have any calibration LUTs, which essentially turns off all LUT calibration and linearizes the contents of the video card.
When you do this, use a 256 grayscale image with evenly spaced steps in Preview.
Yes, I do see this in Apple Preview viewing a 21 step wedge TIFF using Adobe RGB (1998) as you advise. Safari and ColorSync Utility too. I don't see it in Photoshop CC (latest version). I don't see it in Lightroom 8.4 in either Library or Develop modules. And this isn't limited to Adobe applications, GraphicConverter 9 matches Photoshop and Lightroom. So yes, there's a bug but it's not affecting all applications equally. It does affect all Apple app's I've tried and it suggests Apple needs better beta testers like many who post here. Andrew Rodney http://www.digitaldog.net/