Black Sabbath on Intrigue Red
#220022 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
3.54:1
Large text only
Not AAA (7:1). Swapping the two colours gives the same number — the ratio does not know which is the text.
APCA
Lc 26.7
Clears Lc 15 — disabled or purely decorative text, which is not meant to be read.
Dark text on a lighter ground.
Colour difference
ΔE00 37.4
different colours
Above 10 — related only in the sense that both are colours.
What the text colour has to become
#ffe0fd 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 2.87:1, ΔE00 34.5.
deuteranopia
Ratio 3.88:1, ΔE00 44.1.
tritanopia
Ratio 4.93:1, ΔE00 43.0.
The weakest of the three is protanopia, where the two are ΔE00 34.5 apart against 37.4 for a trichromat — still clearly two colours.
Both colours have pages of their own: Black Sabbath ·Intrigue Red · the same pair the other way round ·all pairs