HueComb

Red Stop

#ff2222

A red that is about as vivid as sRGB can show at this lightness. It is light — black text sits on it comfortably, white text does not.

Hex

#ff2222

RGB

255, 34, 34

OKLCh

63.8% 0.247 28.0°

CIELAB (D50)

55.6, 77.7, 59.5

What is true of this colour, and of no other

  • 7 other named colours sit within ΔE00 2 of it.
  • 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 63.3; on black, Lc -38.3. 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 44.1 and 48.3 and 52.7 — no red cone.

Text on this colour

White text

3.82:1 — large text only

Black text

5.50:1 — passes AA

Black text is the better of the two at5.50:1. That is enough for body text.

As text on white, it needs to change

#ef0011 is the nearest colour of the same hue that passes AA on white, at 4.50:1. Only the lightness moved, and some saturation was given up to stay inside sRGB.

Try it against your own background

The same colour, with one cone missing

As you see it

#ff2222

protanopia

#646427 · ΔE00 44.1

deuteranopia

#969600 · ΔE00 48.3

tritanopia

#bcbc00 · ΔE00 52.7

Run a whole palette through all three

The twelve nearest named colours

Ranked by CIEDE2000 — perceptual distance, not hex arithmetic. The closest isTraffic Red at ΔE00 0.822: below 1.0 — an ordinary observer cannot tell these apart, even side by side. What the numbers mean.

4 of these have no page of their own: pages exist for the 4,961 colours the dataset marks as good names.