TPAC, 19 October 2020

By Chris Lilley, W3C

CSS Color 4

Adds calibrated RGB spaces (beyond sRGB)

display-p3, a98-rgb, prophoto-rgb, rec2020

Adds CIE Lab, LCH (D50, Bradford)

Sample code to reassure wary implementers

CSS Color 4

Adds colorspaces defined by downloadable ICC profiles

Several calibrated CMYK and n-color examples

device-cmyk redefined to use FOGRA-39 behind the scenes

Discouraging "naive" CMYK to RGB conversion

don't do this

Encouraging ICC CMYK to RGB interconversion

do this

CSS Color 4 Implementations

Safari implements color(display-p3) since 2016; now implementing at least Lab, LCH

Chrome desire to implement, TAG review

Firefox asking pre-implementation, platform consistency questions

CSS Color 4 Implementations

BFO (CSS to PDF) implements all of CSS Color 4

Test suite in development

Outstanding issues

Gamut mapping

Color serialization

Interpolation and currentColor

Choice of computational space (linear light XYZ, perceptually uniform Lab or LCH, legacy sRGB

CSS Color 5

color-mix mixes 2 colors (in LCH by default)

color-contrast finds most contrasting color (relative luminance) from a list

color-adjust & relative color syntax modifies a color

Color HDR

Unofficial draft, not yet adopted

Adds Rec BT.2100 with HLG or PQ

Adds Jzazbz & JzCzHz


Requires compositing in CIE XYZ (not sRGB!! or even NTSC!!!)

Media Queries 5

color-gamut media query (srgb |p3|rec2020)

dynamic-range media query (standard|high)

And for separate video planes: