Dragon’s Fire on Porcini
#fc4a14 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
1.69:1
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 18.8
Clears Lc 15 — disabled or purely decorative text, which is not meant to be read.
Dark text on a lighter ground.
Colour difference
ΔE00 24.4
different colours
Above 10 — related only in the sense that both are colours.
What the text colour has to become
#8a2100 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 2.34:1, ΔE00 23.9.
deuteranopia
Ratio 1.48:1, ΔE00 15.3.
tritanopia
Ratio 1.07:1, ΔE00 1.8.
The weakest of the three is tritanopia, where the two are ΔE00 1.8 apart against 24.4 for a trichromat — effectively one colour. If anything on your interface depends on telling these apart, it needs a second signal.
Both colours have pages of their own: Dragon’s Fire ·Porcini · the same pair the other way round ·all pairs