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I first saw this post in 2009 or so, and it was eye-opening. I found it while googling for why colours shifted when I resized images, as back then there wasn't
by lstamour 8y ago
I first saw this post in 2009 or so, and it was eye-opening. I found it while googling for why colours shifted when I resized images, as back then there wasn't much awareness of this issue. But it's much less prevalent now. Related -- scaling algorithms: https://en.wikipedia.org/wiki/Image_scaling#Algorithms https://en.wikipedia.org/wiki/Image_scaling#Algorithms
You don't often find browsers disagreeing in 2019 on how to render things, but image colour -- even on the same MacOS (retina) platform -- appear to be one of those things they disagree on still: https://content.screencast.com/users/LouisStAmour/folders/Snagit/media/5089fccd-17f6-4220-9922-91a022838115/2019-01-03_20-37-12.png https://content.screencast.com/users/LouisStAmour/folders/Sn... Safari on the left, Firefox in the middle and Chrome on the right. So you can try it for yourself, the test page is at http://www.ericbrasseur.org/gamma_dalai_lama.html http://www.ericbrasseur.org/gamma_dalai_lama.html
If this isn't esoteric enough, I know of at least one major broadcast media company (Bell's crave.ca) that doesn't properly encode their HDTV 720p videos in MP4 to flag to the browser they're in Rec 709 colour space, and so the compression artifacts, designed to be invisible in Rec 709 are extremely visible on a wide gamut P3 display.
Of course, these flags were only recently respected on all platforms. Chrome on Windows as of Oct 2016: https://bugs.chromium.org/p/chromium/issues/detail?id=655417#c18 https://bugs.chromium.org/p/chromium/issues/detail?id=655417... and Firefox (err, actually still not fixed, it depends on the codec...) https://bugzilla.mozilla.org/show_bug.cgi?id=1300170#c87 https://bugzilla.mozilla.org/show_bug.cgi?id=1300170#c87
But colour space is increasingly something you have to pay attention to, as displays improve beyond sRGB -- yet ironically, it's also getting easier to ignore as the latest stepping stone towards Rec 2020, the DCI-P3 colour space, is shared between PC and movie industries. https://en.wikipedia.org/wiki/DCI-P3#2015-2016 https://en.wikipedia.org/wiki/DCI-P3#2015-2016 (Personally I refuse to buy any display or device that plays back video if it doesn't have a P3 display, ideally OLED)
FYI, you can test for colour gamut device support with CSS to serve wide-gamut colours -- but oddly enough, again, no Firefox support. :( https://developer.mozilla.org/en-US/docs/Web/CSS/@media/color-gamut https://developer.mozilla.org/en-US/docs/Web/CSS/@media/colo... FF bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1422237 https://bugzilla.mozilla.org/show_bug.cgi?id=1422237
- jacobolus 8y ago> back then [in 2009] there wasn't much awareness of this issue I haven’t noticed too much change in the general awareness of this problem between the 1990s and today. Experts have always known the right thing to do and people have been talking about these problems as long as there has been image processing, (e.g. Poynton’s Gamma FAQ dates from sometime before 1998 http://poynton.ca/notes/colour_and_gamma/GammaFAQ.html http://poynton.ca/notes/colour_and_gamma/GammaFAQ.html) but it’s new to everyone at some point, and newcomers perennially screw up. The annoying thing is that there are folks who continue to screw up (like Adobe Photoshop) who should really know better. Backwards compatibility shouldn’t be an excuse to continue with broken implementations for decades.
- lstamour 8y agoOh, the broken implementations don't stop at backwards compatibility -- Lightroom CC, their new Cloud product, last I checked, prefers to send sRGB to Photoshop (!) unlike the traditional Lightroom which fully supports preserving embedded colour profiles when exporting. It's been a couple weeks since I looked into this but the instructions in this post https://lightroomkillertips.com/keeping-your-color-consistent-between-lightroom-and-photoshop/ https://lightroomkillertips.com/keeping-your-color-consisten... apply to Classic Lightroom if I recall correctly, and the modern "cloud" Lightroom CC only exports wide gamut correctly when set to export as uncompressed TIFF 16-bit. Everything else tries to export as sRGB automatically, which sucks for print or DCI-P3 workflows. Also, I'm trying to find details on Apple's P3 profiles in how they differ from standard projection profiles for the movie industry to maintain compatibility with sRGB gamma, but there's not as much online as I expected about it. In my search for info, I came across https://ninedegreesbelow.com/photography/lcms-make-icc-profiles.html https://ninedegreesbelow.com/photography/lcms-make-icc-profi... which seems like a useful resource for Linux/FLOSS folks. Ah. Found it, a source for the differences between "Display P3" and movie-theatre P3. Here's a link to the relevant section of the video, on colour spaces: https://developer.apple.com/videos/play/wwdc2016-501/?time=2740 https://developer.apple.com/videos/play/wwdc2016-501/?time=2... And here's a good discussion on why D60 was chosen for film projection while D65 is used by modern computers for sRGB/Rec 709 compatibility: https://www.liftgammagain.com/forum/index.php?threads/dci-p3-theatrical-vs-d65-different-white-points.11109/ https://www.liftgammagain.com/forum/index.php?threads/dci-p3... and here's a bit on the technical details of ICC profiles and CIE XYZ numeric representations of colours: https://ninedegreesbelow.com/photography/xyz-rgb.html https://ninedegreesbelow.com/photography/xyz-rgb.html