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The very first example is wrong. It tries to debunk a WCAG standard for text contrast using a survey of normal people. The point of the WCAG standard is to acco

The very first example is wrong. It tries to debunk a WCAG standard for text contrast using a survey of normal people. The point of the WCAG standard is to accommodate non-normal people, so any survey of normals is entirely meaningless to the discussion.

mark-r 7y ago
The formulas for computation of contrast are not influenced by non-normal eyesight considerations, it's only the acceptance thresholds that are affected. The computation of lightness in particular is based on weighting for average sensitivity to RGB. I've been dissatisfied with their formula for a long time, even though I have normal vision myself.
- zokier 7y ago
  The comment from Andrew Somers[1] there is well worth a read. The salient quote here is > The method used for the WCAG 2.x contrast is, as I’ve discussed elsewhere, inconsistent with human perception models [1] https://uxmovement.com/buttons/the-myths-of-color-contrast-accessibility/#comment-92567 https://uxmovement.com/buttons/the-myths-of-color-contrast-a...
  - mark-r 7y ago
    Thanks for pointing that out, I missed it. It's refreshing to hear from someone who seems to know what they're talking about; I've looked at the WCAG document itself and haven't found a lot of justification for their recommendations.
    - jacobolus 7y ago
      You should think of it as a weak heuristic pointing in vaguely the right direction, rather than a careful scientifically validated metric. Similar in its technical sloppiness the “color rendering index” advertised on light bulbs.
chadlavi 7y ago
Thank you! I came here to say this same thing. Who cares what your twitter survey said?
james_s_tayler 7y ago
It's not wrong. It seems right to me. The survey also included those with colorblindness.
- zdragnar 7y ago
  When the two are side by side, the White text appeared easier to read. When covering one up and only looking at the other, then the other way around, the black text was certainly crisper for me, and someone else here pointed it out as well. As such, I wonder how the survey was conducted. It may or may not be useful at all otherwise. One thing that also seems to intuitively make this seem to make sense- driving at night, it is much harder to read gas prices from the big light signs when green is used than when red is... The lighter (and or brighter?) green simply bleeds over much more.
- cjensen 7y ago
  The second example did... but not all colorblindness is equal. What you want is something readable by as many people as possible. The goal is not to make the most people happiest.

mark-r 7y ago

The formulas for computation of contrast are not influenced by non-normal eyesight considerations, it's only the acceptance thresholds that are affected. The computation of lightness in particular is based on weighting for average sensitivity to RGB. I've been dissatisfied with their formula for a long time, even though I have normal vision myself.

zokier 7y ago
The comment from Andrew Somers[1] there is well worth a read. The salient quote here is > The method used for the WCAG 2.x contrast is, as I’ve discussed elsewhere, inconsistent with human perception models [1] https://uxmovement.com/buttons/the-myths-of-color-contrast-accessibility/#comment-92567 https://uxmovement.com/buttons/the-myths-of-color-contrast-a...
- mark-r 7y ago
  Thanks for pointing that out, I missed it. It's refreshing to hear from someone who seems to know what they're talking about; I've looked at the WCAG document itself and haven't found a lot of justification for their recommendations.
  - jacobolus 7y ago
    You should think of it as a weak heuristic pointing in vaguely the right direction, rather than a careful scientifically validated metric. Similar in its technical sloppiness the “color rendering index” advertised on light bulbs.

chadlavi 7y ago

Thank you! I came here to say this same thing. Who cares what your twitter survey said?

james_s_tayler 7y ago

It's not wrong. It seems right to me. The survey also included those with colorblindness.

zdragnar 7y ago
When the two are side by side, the White text appeared easier to read. When covering one up and only looking at the other, then the other way around, the black text was certainly crisper for me, and someone else here pointed it out as well. As such, I wonder how the survey was conducted. It may or may not be useful at all otherwise. One thing that also seems to intuitively make this seem to make sense- driving at night, it is much harder to read gas prices from the big light signs when green is used than when red is... The lighter (and or brighter?) green simply bleeds over much more.
cjensen 7y ago
The second example did... but not all colorblindness is equal. What you want is something readable by as many people as possible. The goal is not to make the most people happiest.