Cover of Night on Flash in the Pan
#494e4f on #ff9977
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
4.05:1
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 46.6
Clears Lc 45 — large or heavy display text.
Dark text on a lighter ground.
Colour difference
ΔE00 48.3
different colours
Above 10 — related only in the sense that both are colours.
What the text colour has to become
#424748 is the nearest colour of the same hue that passes AA on #ff9977, at 4.50:1. Only the lightness moved — which is the point: your colour stays recognisably your colour.
And to someone missing a cone
protanopia
Ratio 3.43:1, ΔE00 39.5.
deuteranopia
Ratio 4.39:1, ΔE00 47.5.
tritanopia
Ratio 5.30:1, ΔE00 60.9.
The weakest of the three is protanopia, where the two are ΔE00 39.5 apart against 48.3 for a trichromat — still clearly two colours.
Both colours have pages of their own: Cover of Night ·Flash in the Pan · the same pair the other way round ·all pairs