Cover of Night on Cherry on Top
#494e4f on #ac495c
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
1.55:1
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 10.6
Below Lc 15: the draft treats this as not text.
Dark text on a lighter ground.
Colour difference
ΔE00 23.3
different colours
Above 10 — related only in the sense that both are colours.
What the text colour has to become
#e5ebec is the nearest colour of the same hue that passes AA on #ac495c, 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 1.24:1, ΔE00 4.9.
deuteranopia
Ratio 1.72:1, ΔE00 18.5.
tritanopia
Ratio 2.18:1, ΔE00 41.8.
The weakest of the three is protanopia, where the two are ΔE00 4.9 apart against 23.3 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: Cover of Night ·Cherry on Top · the same pair the other way round ·all pairs