Regarding contrast P'atch fixes"

In reference to Sam’s query regarding adding SCs to WCAG 2.x contrast to improve it, In the fall of 2019, I had been working on some “patch” SCs for WCAG 2.2 to create stepping stones to the contrast metric for Silver, but I was not able to get them researched and fully formed to submit by the deadline, as I was too busy preparing the larger work for Silver.

To quickly sum up some of what I had been proposing/working on for contrast for 2.2, that got stuck on the back burner.

Minimum background brightness for dark text on a light background, requiring the background be no darker than #a0a0a0 (Addresses the 2.x dark pairs failure).

Minimum padding around text of 1em, *if* the text container’s background (div) is more than 2:1 contrast with the larger surrounding background. (addresses local adaptation issues)

Minimum contrast for body text as above at 7:1 (11:1 preferred).  Body text defined as more than two lines of related text in a block or column.

No fonts lighter than 300 weight for body text, and no smaller than 14px for body text (16px recommended) (addresses important spatial frequency limitations on perception).

These do not address the issues with reverse polarity of light text on dark, though that problem is solved with APCA, which also includes corrections for the above, which is why we have been discussing an “alternate” SC as outlined on the Wiki here: 

https://www.w3.org/WAI/GL/low-vision-a11y-tf/wiki/Ideas_for_scope_and_work_topics_(August_2021)#Proposed_WCAG_2.3_Alternate_Contrast_SC_.28APCA_lite.29


Supplemental Guidance

Is this on GitHub where I can fork it so I can work on it? The first thing I’d like to address is the ambiguous nature of a number of entries. There is a number of uses of terms like “many” or “most” with no real quantification or supporting references. I think starting there, the rest of the document will start to fall into place.

ALSO,

If you are interested, this is a link to the “Introduction to Color for Accessibility” that I wrote for the Mozilla site in their accessibility section. It’s in a slightly different format, but covers a lot of what I’d think should be in the “Supplemental Guidance”.

https://developer.mozilla.org/en-US/docs/Web/Accessibility/Understanding_Colors_and_Luminance

This is written in terms of a general scope of visual accessibility issues and the relation to web content.


Thank you!


Andy