Stop using WCAG 2 for color contrast.

Simon Schmidt
3 min readJan 10, 2023

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I know, I know: Its still the standard. But its shit and there is a better alternative. Give me 5min to explain.

Its hard to argue with authorities — and WCAG 2 is an authority. Its even engrained in law in many countries with the noble aim to reduce A11Y pain. Government websites must be built in WCAG 2 compliance. Even the wide ranging European Accessibility Act will likely be enforced with reference to WCAG 2.

But did you ever use WCAG 2 for practical design decisions? Did it help you? Apart from my very early career days I never had the impression WCAG 2 was a good guideline and helped me find a better solution. Alas I never could put my finger on it and why I felt it too lax on one issue and too strict on another.

What had a lasting impression on me was when the new algorithm that will likely power WCAG 3 was released as a draft. Its called APCA and is all the rage since some time. If you follow the link you can dive into a deep rabbit hole of perception science. However the hype is real and its justified and it made me hate WCAG 2 contrast checks with passion. Grab the great Zebra Figma Plugin for comparison here. There are lots of improvements in APCA that have been listed everywhere, e.g.

  • Modelled after human perception science and less as a linear mathematical function
  • Background vs. foreground not interchangable, aka context matters
  • Consideration of a multitude of text sizes and weights (think variable fonts) instead of just two

But the most important thing: it just works when WCAG 2 struggles:

Which one would you prefer?

WCAG 2 seems to consistently undervalue brightness as a means of contrast. Its just useless to determine a button text color — if there is any doubt about it.

Thank you for stating the obvious WCAG 2

Now following a standard is mostly a political decision. As we can expect WCAG 3 hopefully some time this year its better to early adopt the better solution instead of building on a soon outdated status quo. Even more so basing design decisions on it that easily outlast those updates. Morally anyway. We should respect the intent of the regulation: Serving the more accessible contrast and not implementing standard XY.

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