Heartbeat
#aa0000
A red that is saturated. It is mid — the hardest range to put text on, either colour struggles.
Hex
#aa0000
RGB
170, 0, 0
OKLCh
46.3% 0.190 29.2°
CIELAB (D50)
35.9, 59.6, 51.3
What is true of this colour, and of no other
- 14 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 sits exactly on the sRGB boundary: at this lightness and hue the gamut has nothing left, and a wider display would show a more colourful version of it.
- As text on white it measures APCA Lc 84.2; on black, Lc -17.8. 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 36.8 and 39.4 and 43.3 — no red cone.
Text on this colour
White text
7.75:1 — passes AA
Black text
2.71:1 — fails AA
White text is the better of the two at7.75:1. That is enough for body text.
The same colour, with one cone missing
As you see it
#aa0000
protanopia
#3c3c05 · ΔE00 36.8
deuteranopia
#606000 · ΔE00 39.4
tritanopia
#7b7b00 · ΔE00 43.3
The twelve nearest named colours
Ranked by CIEDE2000 — perceptual distance, not hex arithmetic. The closest isVelvet Volcano at ΔE00 0.365: below 1.0 — an ordinary observer cannot tell these apart, even side by side. What the numbers mean.
- Velvet VolcanoΔE00 0.365 · #ab0102
- Red DoorΔE00 0.408 · #ac0000
- Red PentacleΔE00 0.816 · #a60000
- Natural LeatherΔE00 0.825 · #a80e00
- Kid IcarusΔE00 0.975 · #a81000
- Cave PaintingΔE00 1.146 · #aa1100
- Stanger RedΔE00 1.223 · #a40000
- Gory RedΔE00 1.287 · #a30800
- Mordant Red 19ΔE00 1.314 · #ae0c00
- Real RedΔE00 1.377 · #a90308
- RufousΔE00 1.702 · #a81c07
- Red GoreΔE00 1.745 · #ad1400
9 of these have no page of their own: pages exist for the 4,961 colours the dataset marks as good names.