Master Chief on Endless Galaxy
#507d2a on #000044
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
3.98:1
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 -27.1
Clears Lc 15 — disabled or purely decorative text, which is not meant to be read.
Light text on a darker ground — the negative sign is the polarity.
Colour difference
ΔE00 59.6
different colours
Above 10 — related only in the sense that both are colours.
What the text colour has to become
#588633 is the nearest colour of the same hue that passes AA on #000044, 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 4.23:1, ΔE00 63.0.
deuteranopia
Ratio 3.84:1, ΔE00 60.3.
tritanopia
Ratio 3.91:1, ΔE00 32.1.
The weakest of the three is tritanopia, where the two are ΔE00 32.1 apart against 59.6 for a trichromat — still clearly two colours.
Both colours have pages of their own: Master Chief ·Endless Galaxy · the same pair the other way round ·all pairs