WCAG 3 is not ready yet

And it won’t be for quite some time.

Table of Contents

In the last couple of weeks, more and more people point at the WCAG 3.0 Working Draft and recommend the adoption of aspects from it that suit their needs, despite the draft clearly stating (emphasis theirs):

These are early drafts of guidelines included to serve as initial examples. They are used to illustrate what WCAG 3.0 could look like and to test the process of writing content. These guideline drafts should not be considered as final content of WCAG 3.0. They are included to show how the structure would work.

W3C Working Groups publish drafts to allow the public and W3C members to give feedback. They are explicitly not meant as a recommendation or even as advice. To quote from the W3C process document (emphasis mine):

Working Drafts do not necessarily represent a consensus of the Working Group with respect to their content, and do not imply any endorsement by W3C or its members beyond agreement to work on a general area of technology.
A Working Draft is suitable for gathering wide review prior to advancing to the next stage of maturity.

What’s the issue with being an early adopter?

In general, web technologies are very good citizens to early adopters like me: They usually come with suitable fallbacks that allow you to use, for example, animations and transitions in 2009 with the fallback of no animation for browsers without support.

With guidelines like WCAG 2.1 and 2.2 (to be released later), the same approach is true. If you use WCAG 2.2 Success Criteria now, the Guidelines are built to be backwards compatible. So you will never break a 2.0 or 2.1 audit by using it.

But WCAG 3 breaks backwards compatibility. This is a conscious move to better adapt the standard to serve different disabilities which WCAG 2 did not sufficiently cover, due to its structure.

That means that WCAG 3 will probably have a different scoring system that does not necessarily overlap with WCAG 2. As far as I know – and my involvement was some time ago – the current plan is to make sure all WCAG 2 conforming pages conform to WCAG 3, too, in some form. They will not in reverse.

So, what about that “new color contrast algorithm”, then?

The visual contrast algorithm that is currently referenced in the WCAG 3 Working Draft, named APCA, is a stark departure from the luminosity contrast algorithm used in WCAG 2.

  • WCAG 2 treats front and background color the same, so inverting the color does not change the calculation. This is notably not how color perception works in practice. You can perceive certain colors better or worse, depending on the surrounding color.
  • WCAG 2 does not take font-size and weight into account, the APCA does.
  • WCAG 2 did not change the required contrast depending on the font, APCA does.

These are all good arguments to change to a new way of measuring contrast, especially as APCA also promises to give designers more color choice. However:

  • Any color combination with APCA needs to be checked for both font-size and weight, making requirements documents and design systems more complicated.
  • Designers compare the used font to the standard, Helvetica-based, APCA lookup table. This feels like an error-prone step to me, considering that this comparison seems to be done on a visual level. It is not only excluding people with visual disabilities from making their own (accessible) font and color choices, but it also brings a certain level of subjectivity into the rating.
  • How the APCA values convert to WCAG 3 ratings is not 100% clear to me. The rating section in the draft (expand the “Rating for Luminance contrast between background and text” for more info) refers to the lookup table values and how you can not meet a number of them and still get a rating. (WCAG 3 aims to not have clear pass/fail criteria, but looser ratings, that give websites the opportunity to be a bit inaccessible and still conform to WCAG to a certain extent.)
  • The – admittedly also draft – design and development information for ”Visual contrast of text” has little actually actionable information at this point: How do I choose colors? How do I make sure my design system complies? How do I measure the colors practically? It has some information on display color calibration and the environment, but in my opinion, those should be relevant for determining the contrast using the algorithm.
  • The APCA algorithm is changed occasionally (last in March 2021). It’s good that it adapts to new research, but it also means that you might use a color that is not sufficient by a later version.

This reads much more complicated to me, compared to the current way of using colors. It is probably more exact, but it trades off clarity. Designers might get to use orange and white, but there is an additional effort on how complicated it is to evaluate and describe accessible designs.

That trade-off might be totally worth it, but there are many questions that need to be answered between now and then.

So, should you use APCA?

The answer is two-fold:

  • For private, non-commercial projects: Sure, go ahead and apply it to the best of your knowledge. There are no restrictions on what you can do, and it might even inform future developments in WCAG.
  • For commercial and public projects: You are probably, through law or policy, required to conform to WCAG 2. That means you cannot rely on APCA for compliance (simply because it does not exist in WCAG 2).

WCAG 3 and the consensus process will probably mean that it takes another 3–5 years until WCAG 3 sees any release. And then WCAG 2 will be still enshrined into a lot of laws and policies. After all, WCAG 3 is a huge monolith of a specification, and the structure that the Working Group wants to use is very complex. You can read about it in the WCAG 3 explainer.

In the meantime, WCAG 2 is there for you. Is it perfect? No. Is the luminosity contrast flawed? Pretty sure. But that should encourage us to take the time to make sure that we don’t make similar choices in WCAG 3. As I have outlined previously on this very blog, I don’t think WCAG 3 is necessary the silver bullet that we think it is.

What is the way forward?

I think exploring APCA and how it works with your particular color needs is a good first step, and the Accessibility Guidelines Working Group probably welcomes that feedback. If you use it, be aware that you might not conform to WCAG 2, and you cannot conform to WCAG 3 (as that does not exist yet).

I’m very worried that some designers might think they should or can use the new contrast algorithm, and then accessibility consultants have to push back and clear up those misunderstandings. It takes up a lot of time, while accessibility consultants have their hands full already.

Additionally, it gives accessibility a bad reputation: “You can’t even agree on what colors we should use. Accessibility makes everything more complicated!”. This already is a common sentiment, and speculating what the future might be, based on an early working draft, will not help with it.

What if…?

In an alternate universe, we would have a modular WCAG (similar to what CSS is doing) where every two years or so we package up new success criteria into a new version. It would have allowed different speeds for different SCs, and in this case, we might have a better understanding on what the way forward would be. And if our rating or evaluation guideline would change, the next version of that Success Criterion could address it.

That said, it is so easy to think in these inconsequential hypotheticals. The W3C consensus is that WCAG 2.2 is published some time next year. WCAG 3 follows when it’s done. It’s a long process, and we need to make sure all our i’s are dotted and the t’s are crossed. Let’s just make sure we don’t get ahead of ourselves and create confusion.

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I'm a web accessibility professional who cares deeply about inclusion and an open web for everyone. I work with Axess Lab as an accessibility specialist. Previously, I worked with Knowbility, the World Wide Web Consortium, and Aktion Mensch. In this blog I publish my own thoughts and research about the web industry.

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Addendum 2021-12-14

Maybe the article did not make that clear: If you use a color that has enough contrast to the algorithm specified in WCAG 2 and the one that is maybe coming in the future, that is great, and it will give your color combination a certain longevity.

Combining both means cutting off obviously hard to read color combinations that are allowed under WCAG 2 while not venturing out of the color space WCAG 2 has inhabited. That means you raise your level of accessibility beyond the minimal requirements of WCAG 2. And that is awesome.

Update 2023-03-28

WCAG 3 is still not ready. In fact, there haven’t been any meaningful updates to the draft since this article was initially published. The proposed charter for the WCAG WG has a completion date of Q2/2026, which is probably unrealistic. (Minor WCAG 2 updates took between 5 and 10 years, but now they want to create an entirely new standard with new testing requirements and documentation in three years?)

Comments & Webmentions





  • 💬
    Craig Francis replied:
    2022-08-28 23:10

    Thanks for the reminder, I’ve been a bit too eager for a better contrast algorithm, but it needs a lot of testing to make sure it is actually better :-)

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