My guess here, to help it make sense, perhaps think in terms of the luminous excitation of "blacklight paint"... If she's having strong reactions, probably to metamers under the right lighting in a real-world environment and not constrained by the gamut of a defined colorspace like some flavor of CMYK or RGB...
Here's a real question for her on the subject, how does she see a blacklight? I expect a true tetrachromat to see it nearly white. But also I wonder if she's sensing a fluorescing that is of sufficiently short wavelength that standard vision can not perceive it.
The implants I have in each eye are different technologies. The right eye has no UV filter, the IOL in the left eye does have a UV filter. When I look at a blacklight with my right eye, it's bright, almost white in appearance.
But looking at the blacklight with my left eye, it looks like what most see, as a very dark purple with almost no visible light.
A friend of mine is an artist who has been experimenting with extreme metamerism, using pigments that radically change perceived color under different light sources, including of course, blacklight.
Since you mention hiking, I wonder if some of the plant life you and your wife encounter have any florescent properties, or perhaps interact with some fungus that does... A portable UV light at night might be interesting...
I am sorry about the licensing issue, it is only temporary during the public beta. And I am providing some exceptions, if you need, send an email to legal@myndex.com
Just can't do an MIT type license right now—and really there's no generic one that really suit what we need right now, so we're working on such a license, one that is reasonably permissive yet prevents some of the issues we've run into. I.e. like with bad actors incorrectly modifying, or reverse engineering and doing so wrongly, or taking it to the cantina at Mos Eisley...
Hi @seanwilson, standards work is nothing BUT compromises it seems.
The reason for the public beta is to find concerns like these.
One of the aspects of APCA that is unique are the many use-case levels that improve design flexibility by focusing contrast values where they are actually needed.
First of all thank you for these comments, I do proactively seek out comments like these as there are too few at the official APCA discussion forum https://github.com/Myndex/SAPC-APCA/discussions
That said:
A px is not a device pixel, it is referenced to the canvas abstraction layer as the canonical CSS reference px. It represents 1.278 arc minutes of visual angle as subtended onto the retina. Or 0.0213° 𝑽𝜽
This is the case with a 96ppi monitor at 28" away.
Visual Angle in arc minutes is what is used in research, and in fact what the Snellen eye chart is based around, 20/20 is based on a capital E that is 5 arc minutes high, where each line is 1 arcmin, and each space between the three horizontal lines is 1 arcmin, where we then find a spatial frequency of 30 cycles per degree.
But that is for minimum acuity .
Minimum acuity is NOT best readability, which needs to be ~2.5 or times larger than the acuity size (critical size). For a standard display a reference distance away, that means an x-height of 9.4px, which is 12 minutes of arc 𝑽𝜽.
Critical size and critical contrast are recited and empirically tested for decades by eminent readability researchers Whittacker, Lovi-Kitchin, Ian Bailey, Legge, et alia.
The font sizes for APCA are based on this, and assuming a reference font like Helvetica with a 0.52 x-height ratio.
ALSO, if you want a "catch all" contrast value,Lc 75 is more appropriate IMO.
NOT SET IN STONE YET
This kind of discussion is good at the forum, so that it can be tracked and considered in the conversations about guidelines.
ALSO
If you want an easy way to use APCA and be fully backwards compatible with the old WCAG 2.x, then try BridgePCA at https://bridgepca.com
WCAG 2.x was neither peer reviewed nor empirically tested—true. However this is not the case for the candidate for WCAG 3, which is APCA. APCA has been in public beta testing for two and a half years, is the subject of ongoing empirical studies, and does already have journal published peer review, as well as independent peer reviews by PhDs, vision scientists, data scientists, and other technologists.
The Medium platform has a lot of good features going for it, yet it literally ignores visual accessibility. For a platform that is entirely based around readable content, one would think that it’d be close to State of the Art, instead of the State of Unreadable.
Nate Baldwin (the developer behind Adobe Leonardo) created the site, and did a pretty amazing job, taking an extremely complicated and nuanced topic (color) and breaking it down into small, bite-size pieces for this encyclopedic reference.
Nate developed the site before AI like GPT were available. Color is a very difficult subject—but the site is filled with the references that it's relating to, so if you want the deeper dive, go to those multi-hundred page references.
As far as the guide to contrast, look at the navigation on the left, and go to the contrast section. The site is set up more like an encyclopedic reference as opposed to a read-from-the-top blog.
https://linktr.ee/Myndex