Graphics contrast - critical principle

Hi everyone,

Thanks for all the feedback on Information graphics contrast [1, 2]. There is one principle involved, which if agreed, means we can refine the wording and continue.

Several people noted the difficulty with testing contrast on complex graphics which have multiple colours, which is true on the face of it.

I think there is a reasonable way to approach this, which I tested by presenting it to 8 people in our design team. They didn’t go pale or get angry, and after a couple of examples it seemed quite reasonable.

We obviously haven’t conveyed it in the SC text well enough yet, but if a few of the respondents could read this and think through the objections, I think we can clear that stumbling block:
https://alastairc.ac/tests/graphics-contrast-explanation.html


The nub of it is that the test should be: For each element of a graphic required for understanding, it is discernible.
That is very different from contrast-testing every combination of elements, and IMHO much more feasible.

In that page I work through a couple of the examples to show what’s needed. It is also worth noting that the current “1.4.1 Use of Color“ catches most current “difficult” examples, the contrast aspect would help catch the remaining ones.

I’ve worked through a dozen examples [3], I’m happy to tackle more so long as they pass the color-alone SC and are different from ones I’ve already done.

Kind regards,

-Alastair

1] https://github.com/w3c/wcag21/issues/9

2] https://www.w3.org/2002/09/wbs/35422/NewSC_20161122/results#xq2

3] https://alastairc.ac/tests/graphic-contrast-test.html