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I am unclear about what happens when I mix those two color spaces in one app. Will the sRGB colors just look paler than without mixing them with the colors of the larger Display P3 color space? Should I be trying to avoid it?

Mick
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  • It may depend on what you are doing in the app. Testing is the best. Try to include a ICC profile in every resource. Choosing correct *intent* is also important. – Giacomo Catenazzi Jan 12 '21 at 09:44
  • Testing is not easy, because it requires at least two test devices to hold against each other. – Mick Jan 14 '21 at 09:34
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    Only two devices, because there are just the sRGB, and the Apple version of P3. The problem it is that the "colour stack" is complex, and trivial changes in a layer/API can affect the result. AFAIK there is no good "can i use" for colours. Else: include profile in every image/logo (where correct colour is important). For UI, just keep the colour codes (differentiation is more important). – Giacomo Catenazzi Jan 14 '21 at 09:49

2 Answers2

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sRGB, P3, and Color Management

If you are developing for iOS, and color is important to your app, you want to support both sRGB (as it is the standard) and also support P3. You may or may not need separate P3/sRGB assets. The system's color management can adjust P3 colors to display on sRGB, though in some cases you might experience clipping.

To take advantage of color management for your images, you want to use tagged (i.e. embedded profile) images for both sRGB and P3. You want P3 images to be 16 bit per channel, PNG, with the P3 profile embedded.

ALSO, if you are having issues with P3 content not displaying properly on sRGB, then in the asset catalog of your Xcode project, provide separate images and colors for both P3 (wide color) and sRGB devices.

Myndex
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    I totally missed the possibility of providing separate color gamuts within the xcassets file. Thanks for pointing out! Makes perfect sense to provide both color profiles and let the iOS choose which one it prefers. At least you will not suffer useless degradation of sRGB ressources on sRGB devices this way - which was my major concern. – Mick Oct 18 '21 at 23:09
  • I have my app icon with Display P3 (16 bits / channel), I can see that the color profile embedded as file inspector shows to as Display P3. The preview shows the correct color however when used in the Asset Catalogue, the colors looked washed. I have even tried providing separate app icons for sRGB and Display P3. Would you know what I am missing? – user1046037 Apr 15 '23 at 17:44
  • @user1046037 it sounds like you're displaying P3 colors on an sRGB display without color management? What kind of display is your development environment where you're viewing the asset catalog? – Myndex Apr 17 '23 at 05:46
  • I am using an Apple Studio display, I can see the correct color when opening the file in Preview (app). The Preview's inspector shows Color profile Display P3 and Color Depth of 16 bits. Somehow while archiving the color profile is not picked because when installed on the iPhone (12 Pro) it shows faded sRGB like colors. Any help on this would be much appreciated – user1046037 Apr 17 '23 at 09:05
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Will the sRGB colors just look paler than without mixing them with the colors of the larger Display P3 color space?

Yes they will, even if you will mix with P3-D65 + sRGB transfer (formally what Display P3 is). That is correct though.

Валерий Заподовников
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  • There is no such thing as "DCI D65" I think you meant *"P3 D65"*. P3 is the colorspace. DCI stands for *Digital Cinema Initiative*, and it does not use a CIE D illuminant, but a CCT of 6300 with a gamma of 1/2.6 in a 12 bit image container for DCDM. Display P3 (P3 D65) is different. While it is using the same primaries as DCI P3, DisplayP3 is using a D65 whitepoint and the sRGB TRC which is piecewise, but nevertheless closer to a 1/2.2 curve. – Myndex Sep 30 '21 at 17:19
  • But also, the OP is asking about iOS development, and Apple has a path for using both sRGB and P3 assets. What Apple suggests is using tagged images. – Myndex Sep 30 '21 at 17:22
  • Thanks, corrected! I know what "D63" is and that it is not D series really. – Валерий Заподовников Sep 30 '21 at 21:04
  • Correct, no one should use "D63" as it does not exist as a CIE D illuminant, but moreover, it's not a D type illuminant, it's a correlated color temperature of 6300K. If it *was* a D series it would be about 6303K (± I did not do an actual calc). – Myndex Oct 01 '21 at 00:42
  • CIE D63 is ~~ 6303.403 K using second radition constant from 2018. And it does exist. It is 6300 K from original c_2 definition. – Валерий Заподовников Oct 01 '21 at 17:12
  • There is no *CIE* D63, but if you have a cite for a CIE publication I'd love to hear about it. The obsolete C was 6774K. The D series are D50 D55 D65 D75. The closest thing to 6300K is F series, F5 is 6350K.... DCI-P3 uses a whitepoint that would *not even qualify* as D, it's not even on the planckian locus. This is because a choice was made to maximize projector output from the Xenon bulb. And just because someone calculates their own D illuminant, it does not make that a "standard." Since at least 2004, the only "CIE standard" illuminants are A & D65. D50 D55 D75 are "just CIE illuminants". – Myndex Oct 01 '21 at 21:11
  • D93 is also offcial, obviously, used in Japan. In practice all D series are unified by one formula. – Валерий Заподовников Oct 02 '21 at 06:47