Is anyone on this list aware that MacOS has problems rendering in Preview / Quicklook and other built-ins (e.g., Photos) when using newer forms of ICC profiles? Described in this stackexchage post: https://apple.stackexchange.com/questions/271825/bug-macos-sierra-preview-qu... The above post is quite open-ended in the problem description. To be more specific: I'm not an expert on this topic, but I can reproduce the problem easily using DisplayCal to make an XYZ LUT profile for my display on Mojave 10.14.6 and using Preview / Quicklook to display images. The rendering glitch is reliably a rolloff to black (clipping) in the bottom quarter tones. I've discussed with another user sees artifacts at top-end too depending on the display connection, i.e., HDMI as opposed DP / DVI. I am in conversation with Florian Höch, the author of DisplayCal over at the forums for his software, and he's investigated the problem and boils the situation down as follows: Höch Quote; //The only DisplayCal profile types compatible with Preview are the ones created by (DisplayCal) default, single curve (or gamma value) + matrix, with baked-in black point compensation, and calibration that maps input zero to output zero (so no black point hue correction possible)// I'm out of my league technically on the following point, but Höch goes on to say: //it’s just cLUT tags, and TRC tags that do not conform to the restrictions I mentioned above. Any A2Bx/B2Ax present, and the problem occurs. You can take any profile that Preview has problems with, remove the cLUT tags, replace the TRC tags, without changing anything else, and voila, Preview will be happy.// He observes that this is almost certainly a bug not an engineering limitation: //cLUT profiles work fine with ColorSync Utility by the way, which can be used instead of Preview to open images.// According to stackexchange post, this problem has been known since at least as early as Sierra. Höch added warnings to users in DisplayCal for any user running 10.8 or later because the problem is very common / repeatable. (Caveat I don't know if anyone can claim it's fully characterized) Adobe CC and other software also are known to work properly with profile configs that glitch on MacOS Preview / Quicklook. So to repeat, is there awareness here about this problem? Anyone here have any insights? What's the right way to engage Apple to get this fixed? I recently submitted "User Feedback" to Apple using their web portal. Ideally, MacOS will respect and render correctly using well-formed ICC profiles (! OMG we're talking Colorsync, people !). But if MacOS refused to accept an unsupported profile in Displays prefpane, it would be a fair compromise to silently barfing up wrong results so many users fall into a pit over MacOS behaving differently than their imaging applications. Thanks IA to anyone for taking the time to consider / respond. DisplayCal and Argyll CMS programs are awesome—And maybe disliked in some quarters because they are free and disruptive to a previously lucrative niche? I should shut my trap here... :) I am a messenger TIA /wire