Purple Climax on Porcini
#8800ff on #d9ae86
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
2.96:1
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 35.9
Clears Lc 30 — the floor: below this the draft considers text not readable at any size.
Dark text on a lighter ground.
Colour difference
ΔE00 57.1
different colours
Above 10 — related only in the sense that both are colours.
What the text colour has to become
#6400bf is the nearest colour of the same hue that passes AA on #d9ae86, 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 3.30:1, ΔE00 67.4.
deuteranopia
Ratio 2.82:1, ΔE00 65.3.
tritanopia
Ratio 3.12:1, ΔE00 59.0.
The weakest of the three is tritanopia, where the two are ΔE00 59.0 apart against 57.1 for a trichromat — still clearly two colours.
Both colours have pages of their own: Purple Climax ·Porcini · the same pair the other way round ·all pairs