Out of the Blue on Ethereal Espresso
#1199ee on #3e2723
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
4.49:1
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 -40.2
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 50.4
different colours
Above 10 — related only in the sense that both are colours.
What the text colour has to become
#1299ee is the nearest colour of the same hue that passes AA on #3e2723, 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 5.13:1, ΔE00 50.7.
deuteranopia
Ratio 4.16:1, ΔE00 49.6.
tritanopia
Ratio 3.36:1, ΔE00 60.9.
The weakest of the three is deuteranopia, where the two are ΔE00 49.6 apart against 50.4 for a trichromat — still clearly two colours.
Both colours have pages of their own: Out of the Blue ·Ethereal Espresso · the same pair the other way round ·all pairs