Highlander on Acoustic Brown
#3a533d on #766b69
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
1.64:1
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 11.6
Below Lc 15: the draft treats this as not text.
Dark text on a lighter ground.
Colour difference
ΔE00 24.8
different colours
Above 10 — related only in the sense that both are colours.
What the text colour has to become
#daf7dc is the nearest colour of the same hue that passes AA on #766b69, at 4.50:1. Only the lightness moved — which is the point: your colour stays recognisably your colour.
And to someone missing a cone
protanopia
Ratio 1.55:1, ΔE00 13.0.
deuteranopia
Ratio 1.69:1, ΔE00 13.3.
tritanopia
Ratio 1.67:1, ΔE00 43.0.
The weakest of the three is protanopia, where the two are ΔE00 13.0 apart against 24.8 for a trichromat — still clearly two colours.
Both colours have pages of their own: Highlander ·Acoustic Brown · the same pair the other way round ·all pairs