Kelp on Cyantific
#4d503c on #77c9c2
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
4.32:1
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 49.9
Clears Lc 45 — large or heavy display text.
Dark text on a lighter ground.
Colour difference
ΔE00 45.1
different colours
Above 10 — related only in the sense that both are colours.
What the text colour has to become
#4a4d39 is the nearest colour of the same hue that passes AA on #77c9c2, 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 4.64:1, ΔE00 43.1.
deuteranopia
Ratio 4.15:1, ΔE00 43.1.
tritanopia
Ratio 3.81:1, ΔE00 47.3.
The weakest of the three is protanopia, where the two are ΔE00 43.1 apart against 45.1 for a trichromat — still clearly two colours.
Both colours have pages of their own: Kelp ·Cyantific · the same pair the other way round ·all pairs