Out of the Blue on Vintage Bloom
#1199ee on #c0b0d0
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
1.52:1
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 15.6
Clears Lc 15 — disabled or purely decorative text, which is not meant to be read.
Dark text on a lighter ground.
Colour difference
ΔE00 34.3
different colours
Above 10 — related only in the sense that both are colours.
What the text colour has to become
#004c7a is the nearest colour of the same hue that passes AA on #c0b0d0, 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 1.36:1, ΔE00 15.2.
deuteranopia
Ratio 1.62:1, ΔE00 20.3.
tritanopia
Ratio 1.90:1, ΔE00 46.9.
The weakest of the three is protanopia, where the two are ΔE00 15.2 apart against 34.3 for a trichromat — still clearly two colours.
Both colours have pages of their own: Out of the Blue ·Vintage Bloom · the same pair the other way round ·all pairs