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Are you suggesting that the black text on blue background in the article is easier to read for certain low-vision individuals, while the white text on blue back

• mzs 7y ago
  The black definitely is easier to read for me. I don't mean which 'looks better' to me but in fact which is easier to read. You can test what someone with lower vision would prefer by looking at that example and closing a laptop screen to 40* or so. Which one can you still read?
  • baddox 7y ago
    I'm not talking about aesthetics. I'm very nearsighted, and when I take my glasses off I can definitely read the white text from a further distance than the black text. But I know there are different types of vision issues, and I don't question that the black text may work better for some. I would just question an algorithm that claims that the black text is better in general than the white.
• jacobolus 7y ago
  No, the black text on blue background is hard to read for everyone, but is overrated by the WCAG’s mediocre heuristic because human visual response to light intensity is not actually logarithmic, but closer to a square root. (Under a particular level of light adaptation; if you allow your eye to adapt for 30 minutes you can move the response curve up or down to see in very dim or very bright conditions.) It would be better to come up with an estimate of plausible ranges of screen brightnesses and a plausible range of surrounding contexts, and then use a real color appearance model to decide on visual contrast at the extremes of those plausible scenarios. But whoever designed the WCAG guideline was either not an expert in human vision or perhaps thought that would be too complicated to use a model which more closely approximated perceptual responses. The WCAG guideline should be seen as nothing more than a loose suggestion, with lots of false negatives. That is, if it says something is illegible, then it should probably be changed. but if it says the contrast is okay, then that should be checked by a better model (or human inspection). Both white-on-medium-blue and black-on-medium-blue buttons are inaccessible and should be avoided if possible.
• jimminy 7y ago
  Try holding a piece of paper over them, so you can only review each independently. In isolation, for me, the white on blue, has contrast bleed which makes the text fuzzy. Again, in isolation, the black on blue is much sharper. Together however, when presented side-by-side, the black on blue feels to be lower contrast. It's almost like my brain is using the black on blue to help compensate the weakness of the white on blue.
• BenFrantzDale 7y ago
  Is it doing perceptual color calculations in sRGB instead of LAB? No wonder the permitted contrast ratios don’t match perception.