Siren Scarlet
#b21d1d
A red that is saturated. It is mid — the hardest range to put text on, either colour struggles.
Hex
#b21d1d
RGB
178, 29, 29
OKLCh
49.3% 0.183 27.3°
CIELAB (D50)
39.3, 57.7, 41.5
What is true of this colour, and of no other
- 13 other named colours sit within ΔE00 2 of it — this part of the space is crowded, and the names here are finer distinctions than most people make.
- It uses 91% of the chroma sRGB can show at this lightness and hue — close enough to the boundary that a wider display would show it slightly more vividly.
- As text on white it measures APCA Lc 81.7; on black, Lc -20.2. The sign is the polarity, which the WCAG ratio discards.
- Built into an eleven-step scale, 10 of the 10 adjacent pairs stay ΔE00 2 apart — see the ramp.
- protanopia and deuteranopia and tritanopia shift it by ΔE00 35.9 and 40.9 and 45.3 — no red cone.
Text on this colour
White text
6.80:1 — passes AA
Black text
3.09:1 — large text only
White text is the better of the two at6.80:1. That is enough for body text.
The same colour, with one cone missing
As you see it
#b21d1d
protanopia
#46461f · ΔE00 35.9
deuteranopia
#686809 · ΔE00 40.9
tritanopia
#838300 · ΔE00 45.3
The twelve nearest named colours
Ranked by CIEDE2000 — perceptual distance, not hex arithmetic. The closest isScarlet Blaze at ΔE00 0.387: below 1.0 — an ordinary observer cannot tell these apart, even side by side. What the numbers mean.
- Scarlet BlazeΔE00 0.387 · #b21f1f
- CarnelianΔE00 0.432 · #b31b1b
- Flamingo FervourΔE00 0.888 · #b42121
- FirebrickΔE00 0.98 · #b22222
- Brick by BrickΔE00 1.021 · #b22122
- Fiery GarnetΔE00 1.064 · #b71e1e
- Boy RedΔE00 1.208 · #b3111d
- Upset TomatoΔE00 1.73 · #b52923
- Tomato SunriseΔE00 1.801 · #aa251b
- Red MenaceΔE00 1.85 · #aa2121
- Ketchup LaterΔE00 1.878 · #a91c1c
- Red InfernoΔE00 1.896 · #bb1e1e
5 of these have no page of their own: pages exist for the 4,961 colours the dataset marks as good names.