Master Chief on Cover of Night
#507d2a on #494e4f
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
1.73:1
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 -13.9
Below Lc 15: the draft treats this as not text.
Light text on a darker ground — the negative sign is the polarity.
Colour difference
ΔE00 27.4
different colours
Above 10 — related only in the sense that both are colours.
What the text colour has to become
#9acb77 is the nearest colour of the same hue that passes AA on #494e4f, 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 1.83:1, ΔE00 27.6.
deuteranopia
Ratio 1.68:1, ΔE00 26.1.
tritanopia
Ratio 1.71:1, ΔE00 17.8.
The weakest of the three is tritanopia, where the two are ΔE00 17.8 apart against 27.4 for a trichromat — still clearly two colours.
Both colours have pages of their own: Master Chief ·Cover of Night · the same pair the other way round ·all pairs