by Kerrick on 5/17/25, 4:26 PM with 74 comments
by seanwilson on 5/18/25, 6:10 AM
https://www.inclusivecolors.com/
So one approach is you create swatches of different colors that go from grade 100 (light) to grade 900 (dark), where the lightnesses are chosen such that all grade 700 colors contrast against grade 100 colors, all grade 800 colors contrast against grade 200 etc.
And then you know red-700 vs gray-100, green-800 vs yellow-200 and so on will contrast without having to check.
If you go to the Contrast menu, you can also explore how much stricter the APCA algorithm (meant to be more accurate) is compared to WCAG. For dark on light colors especially, APCA is much stricter about what contrast so you really shouldn't use WCAG for dark themes.
Also, if you go to the Examples menu and check out the Tailwind and IBM Carbon color palettes, you can see how the swatches in hand designed palettes vary their saturation and hue across grades in a non-linear way. So automatically picking if white/black contrasts the best is more straightforward (like the article mentions), but for more deliberate/branded palettes, you can't just generate a color with a simple lightness component shift, so this is more open ended.
by qfr on 5/17/25, 6:13 PM
--text: lch(from var(--bg) calc((49.44 - l) * infinity) 0 0);
by jjcm on 5/17/25, 10:01 PM
For those making anything at a production scale where you need wcag compliance however, I'd avoid this and leverage a proper semantic token layer. Semantic tokens will help both accelerate your dev cycle, and they'll help guarantee proper contrast ratios in a way that looks visually better than just switching your foreground layer to black or white. The great thing about a semantic token layer is they're extremely easy to theme, which means you get light/dark theming for very little additional cost. You can also create separate WCAG2 / APCA accessible themes, should your brand color be one of the ones that WCAG2 has issues with - will get you compliance while still providing a better visual contrast option.
This is kind of my niche domain specialty - I run the variables/tokens stream at Figma, and I've worked on the dark mode implentation for both Figma and Atlassian. Happy to answer any questions about tokens/themes/accessible color.
by mediumsmart on 5/17/25, 6:09 PM
Cant someone take a look at the buttons before the large project ships? Alternatively make it mandatory to never have black text on a dark button and tell every team member including the large ones.
Interesting to read about the perceptual contrast vs mathematical - I did not know that. Going to integrate that into my workflow.
by politelemon on 5/17/25, 6:19 PM
by econ on 5/18/25, 12:05 AM
https://i.sstatic.net/18bQt.png
I forget the calculation but thinking about it you can probably just take the average of the 3 rgb values and compare them(?) It would produce a low value for blue and give preference to white text.
by jbritton on 5/17/25, 6:43 PM
by atum47 on 5/17/25, 7:32 PM
https://youtu.be/tUJvE4xfTgo?si=vFlegFA_7lzijfSR (warning: video is in Portuguese)
by rendaw on 5/18/25, 2:36 AM
What really needs a fix is when you have text over an image or other diverse background (like, sticky/fixed text over a scrolling background) and need to have it always visible. And... this doesn't help at all.
So not only does this only (maybe) help in very questionable circumstances, they needed to come up with an entirely new verb for it, it has an anemic feature set (only selects black or white), and they did it with the worst possible contrast selection algorithm (doesn't select the choice with the most perceptual contrast). Way to go!
by andix on 5/17/25, 9:13 PM
It will take some time until this feature is broadly available, and I'm having some doubt that it will be implemented in the same (or correct) way on all platforms.
by ZYbCRq22HbJ2y7 on 5/17/25, 11:10 PM
by akkartik on 5/18/25, 1:07 AM
https://akkartik.name/post/2025-04-04-devlog
One difference in my approach is: it's an authoring-time tool. If no sufficiently contrasting color exists you get an error. And so you have to change the background until there is one.
by naggie on 5/18/25, 8:24 AM
by lancekey on 5/18/25, 3:14 AM
by Hyperlisk on 5/18/25, 3:07 AM
by crtasm on 5/17/25, 5:42 PM
by dp-hackernews on 5/17/25, 6:53 PM
"Color Wheel: The Basic Color Theory for Artists and Designers" https://dessign.net/color-wheel-theory/
by flysand7 on 5/17/25, 11:14 PM
by HocusLocus on 5/18/25, 3:40 AM
by refulgentis on 5/17/25, 6:10 PM
- Their work does ensure contrast.
- The white on blue clearly has less contrast, not more. (squinting is a cheap way to test, or, walking backwards from your monitor)
With APCA, backgrounds around L* 60 tend to still allow white foregrounds, which is aesthetically closer to what the eye wants.
A black foreground would have more contrast regardless, even by APCA.
To be fair, this is how APCA is almost always demonstrated as a win over the long-running standard, so people run with the premise that the demo image of APCA is more contrast, rather than "ours say you'll have enough contrast to be accessible with a white foreground, even if it also says the contrast would be higher with a black foreground".
(source: in 2020 built color system around the same science, enabling latest iterations of Material theming)
