Acoustic Brown on Master Chief
#766b69 on #507d2a
Body text at this size
And the smaller size most interfaces actually use for paragraphs — the size that decides whether a pair is usable.
Caption text, which almost nothing passes.
WCAG 2.1
1.06:1
Fails AA
Not AAA (7:1). Swapping the two colours gives the same number — the ratio does not know which is the text.
APCA
Lc 0.0
Below Lc 15: the draft treats this as not text.
Too close to call.
Colour difference
ΔE00 28.0
different colours
Above 10 — related only in the sense that both are colours.
What the text colour has to become
#fff3f1 is the nearest colour of the same hue that passes AA on #507d2a, at 4.50:1. Only the lightness moved, and some chroma was given up to stay inside sRGB — which is the point: your colour stays recognisably your colour.
And to someone missing a cone
protanopia
Ratio 1.14:1, ΔE00 20.8.
deuteranopia
Ratio 1.01:1, ΔE00 18.1.
tritanopia
Ratio 1.03:1, ΔE00 44.8.
The weakest of the three is deuteranopia, where the two are ΔE00 18.1 apart against 28.0 for a trichromat — still clearly two colours.
Both colours have pages of their own: Acoustic Brown ·Master Chief · the same pair the other way round ·all pairs