Acoustic Brown on Ballet
#766b69 on #f7d5d4
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
3.78:1
Large text only
Not AAA (7:1). Swapping the two colours gives the same number — the ratio does not know which is the text.
APCA
Lc 55.4
Clears Lc 45 — large or heavy display text.
Dark text on a lighter ground.
Colour difference
ΔE00 34.4
different colours
Above 10 — related only in the sense that both are colours.
What the text colour has to become
#6a5f5d is the nearest colour of the same hue that passes AA on #f7d5d4, 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 3.71:1, ΔE00 33.2.
deuteranopia
Ratio 3.82:1, ΔE00 33.8.
tritanopia
Ratio 3.85:1, ΔE00 37.2.
The weakest of the three is protanopia, where the two are ΔE00 33.2 apart against 34.4 for a trichromat — still clearly two colours.
Both colours have pages of their own: Acoustic Brown ·Ballet · the same pair the other way round ·all pairs