Nickel on Master Sword Blue
#929292 on #00ffee
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
2.45:1
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 43.1
Clears Lc 30 — the floor: below this the draft considers text not readable at any size.
Dark text on a lighter ground.
Colour difference
ΔE00 33.4
different colours
Above 10 — related only in the sense that both are colours.
What the text colour has to become
#666666 is the nearest colour of the same hue that passes AA on #00ffee, 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 2.77:1, ΔE00 24.7.
deuteranopia
Ratio 2.28:1, ΔE00 22.1.
tritanopia
Ratio 1.76:1, ΔE00 24.2.
The weakest of the three is deuteranopia, where the two are ΔE00 22.1 apart against 33.4 for a trichromat — still clearly two colours.
Both colours have pages of their own: Nickel ·Master Sword Blue · the same pair the other way round ·all pairs