Hacker News Reader

Comment by js2 | Hacker News Reader

What am I missing here? In iOS 5, it's black on blue vs black on green. Now it's white on blue vs white on green. Contrast between text and background looks the same to whether green or blue.

In general, Apple has lowered contrast throughout the UI over the years. There's an accessibility setting for high contrast if you need it.

View on HN

Green has higher luminance than blue at equivalent saturation. The values for SMS and iMessage background colors are, respectively and in sRGB, #00CC46 and #0080FF, corresponding to relative luminance values of 0.436 and 0.227 according to the WCAG 2 formula.

With white foreground text, this gives a contrast ratio of 2.15:1 for SMS and 3.79:1 for iMessage. WCAG 2.x AA level compliances requires a contrast ratio of at least 4.5:1 for normal text and at least 3:1 for large text.

https://www.w3.org/WAI/WCAG21/Understanding/contrast-minimum...

Thanks! If you have a calculations workflow already, what would the contrast ratios (even if approximate) be for old iOS? To a human eye it truly looks like SMS got way worse whereas iMessage stayed around the same.

The pre-iOS 7 graphics have black text over a non-uniform background color as compared to white text over a uniform background color. This gives us ranges instead of a single value, but even in the worst case, black is a vastly more legible foreground color:

           | iOS 5-6     | iOS 7+ |
  ---------+-------------+--------+
  SMS      | 11.3 - 13.4 | 2.2    |
  iMessage | 11.8 - 14.1 | 3.8    |

Thank you. FWIW, here is it under iOS 16 with Accessibility > Display & Text Size > Increase Contrast turned on.

https://imgur.com/a/b61lmAf

To my eyes, the green/blue doesn't make much difference in terms of legibility. I obviously find the reduced contrast throughout iOS annoying and keep increase contrast turned on.

Contrast ratio for white on green is only 2.15:1 : https://webaim.org/resources/contrastchecker/?fcolor=FFFFFF&...

Whereas for black on green it's 9.72:1 : https://webaim.org/resources/contrastchecker/?fcolor=000000&...

Reply on news.ycombinator.com