Flirt on Black Sabbath
#7a2e4d on #220022
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
2.13:1
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 -11.4
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 21.5
different colours
Above 10 — related only in the sense that both are colours.
What the text colour has to become
#b3617f is the nearest colour of the same hue that passes AA on #220022, 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 1.86:1, ΔE00 16.0.
deuteranopia
Ratio 2.27:1, ΔE00 23.2.
tritanopia
Ratio 2.65:1, ΔE00 27.5.
The weakest of the three is protanopia, where the two are ΔE00 16.0 apart against 21.5 for a trichromat — still clearly two colours.
Both colours have pages of their own: Flirt ·Black Sabbath · the same pair the other way round ·all pairs