Opera on Intrigue Red
#816575 on #b24648
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 19.5
different colours
Above 10 — related only in the sense that both are colours.
What the text colour has to become
#ffe2f2 is the nearest colour of the same hue that passes AA on #b24648, at 4.50:1. Only the lightness moved, and some chroma was given up to stay inside sRGB — which is the point: your colour stays recognisably your colour.
And to someone missing a cone
protanopia
Ratio 1.27:1, ΔE00 17.5.
deuteranopia
Ratio 1.04:1, ΔE00 21.9.
tritanopia
Ratio 1.33:1, ΔE00 8.3.
The weakest of the three is tritanopia, where the two are ΔE00 8.3 apart against 19.5 for a trichromat — still two colours, but a closer call than it looks to you.
Both colours have pages of their own: Opera ·Intrigue Red · the same pair the other way round ·all pairs