Kelp on Florida’s Alligator
#4d503c on #664422
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
1.05:1
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 17.9
different colours
Above 10 — related only in the sense that both are colours.
What the text colour has to become
#b9bda6 is the nearest colour of the same hue that passes AA on #664422, 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 1.13:1, ΔE00 6.8.
deuteranopia
Ratio 1.01:1, ΔE00 8.8.
tritanopia
Ratio 1.09:1, ΔE00 18.8.
The weakest of the three is protanopia, where the two are ΔE00 6.8 apart against 17.9 for a trichromat — still two colours, but a closer call than it looks to you.
Both colours have pages of their own: Kelp ·Florida’s Alligator · the same pair the other way round ·all pairs