Panorama on Out of the Blue
#327a88 on #1199ee
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
1.59:1
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 14.7
Below Lc 15: the draft treats this as not text.
Dark text on a lighter ground.
Colour difference
ΔE00 20.6
different colours
Above 10 — related only in the sense that both are colours.
What the text colour has to become
#00323a is the nearest colour of the same hue that passes AA on #1199ee, 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 1.62:1, ΔE00 20.2.
deuteranopia
Ratio 1.58:1, ΔE00 18.9.
tritanopia
Ratio 1.31:1, ΔE00 7.7.
The weakest of the three is tritanopia, where the two are ΔE00 7.7 apart against 20.6 for a trichromat — still two colours, but a closer call than it looks to you.
Both colours have pages of their own: Panorama ·Out of the Blue · the same pair the other way round ·all pairs