Dwarf Fortress on Shadow Play
#1d0200 on #2d1403
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
1.14:1
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 0.0
Below Lc 15: the draft treats this as not text.
Too close to call.
Colour difference
ΔE00 7.8
clearly different
Between 5 and 10 — nobody would call these the same colour.
What the text colour has to become
#a1786e is the nearest colour of the same hue that passes AA on #2d1403, 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 1.13:1, ΔE00 7.5.
deuteranopia
Ratio 1.15:1, ΔE00 8.2.
tritanopia
Ratio 1.17:1, ΔE00 8.3.
The weakest of the three is protanopia, where the two are ΔE00 7.5 apart against 7.8 for a trichromat — still two colours, but a closer call than it looks to you.
Both colours have pages of their own: Dwarf Fortress ·Shadow Play · the same pair the other way round ·all pairs