Wild Thing on Belladonna
#654243 on #220011
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
2.24:1
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 -11.9
Below Lc 15: the draft treats this as not text.
Light text on a darker ground — the negative sign is the polarity.
Colour difference
ΔE00 20.1
different colours
Above 10 — related only in the sense that both are colours.
What the text colour has to become
#967070 is the nearest colour of the same hue that passes AA on #220011, 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 2.16:1, ΔE00 20.1.
deuteranopia
Ratio 2.28:1, ΔE00 21.0.
tritanopia
Ratio 2.36:1, ΔE00 24.9.
The weakest of the three is protanopia, where the two are ΔE00 20.1 apart against 20.1 for a trichromat — still clearly two colours.
Both colours have pages of their own: Wild Thing ·Belladonna · the same pair the other way round ·all pairs