Atlas Cedar on Kelp
#5ca0a7 on #4d503c
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
2.79:1
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 -30.9
Clears Lc 30 — the floor: below this the draft considers text not readable at any size.
Light text on a darker ground — the negative sign is the polarity.
Colour difference
ΔE00 34.6
different colours
Above 10 — related only in the sense that both are colours.
What the text colour has to become
#85cad1 is the nearest colour of the same hue that passes AA on #4d503c, 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 2.98:1, ΔE00 34.8.
deuteranopia
Ratio 2.68:1, ΔE00 34.3.
tritanopia
Ratio 2.67:1, ΔE00 41.8.
The weakest of the three is deuteranopia, where the two are ΔE00 34.3 apart against 34.6 for a trichromat — still clearly two colours.
Both colours have pages of their own: Atlas Cedar ·Kelp · the same pair the other way round ·all pairs