Shadow Play on Grapest
#2d1403 on #880066
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
1.85:1
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 12.5
Below Lc 15: the draft treats this as not text.
Dark text on a lighter ground.
Colour difference
ΔE00 30.5
different colours
Above 10 — related only in the sense that both are colours.
What the text colour has to become
#cfad97 is the nearest colour of the same hue that passes AA on #880066, 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 1.46:1, ΔE00 33.8.
deuteranopia
Ratio 2.04:1, ΔE00 30.0.
tritanopia
Ratio 2.49:1, ΔE00 23.2.
The weakest of the three is tritanopia, where the two are ΔE00 23.2 apart against 30.5 for a trichromat — still clearly two colours.
Both colours have pages of their own: Shadow Play ·Grapest · the same pair the other way round ·all pairs