Ballet on Opera
#f7d5d4 on #816575
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
3.81:1
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 -59.0
Clears Lc 45 — large or heavy display text.
Light text on a darker ground — the negative sign is the polarity.
Colour difference
ΔE00 34.5
different colours
Above 10 — related only in the sense that both are colours.
What the text colour has to become
#ffeaea is the nearest colour of the same hue that passes AA on #816575, 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 3.85:1, ΔE00 35.6.
deuteranopia
Ratio 3.79:1, ΔE00 34.9.
tritanopia
Ratio 3.73:1, ΔE00 34.0.
The weakest of the three is tritanopia, where the two are ΔE00 34.0 apart against 34.5 for a trichromat — still clearly two colours.
Both colours have pages of their own: Ballet ·Opera · the same pair the other way round ·all pairs