HueComb

Cerulean

#55aaee

A blue that is muted. It is light — black text sits on it comfortably, white text does not.

Hex

#55aaee

RGB

85, 170, 238

OKLCh

71.4% 0.129 245.2°

CIELAB (D50)

66.5, -10.8, -42.5

What is true of this colour, and of no other

  • 2 other named colours sit within ΔE00 2 of it.
  • It uses 81% of the chroma sRGB can show at this lightness and hue.
  • As text on white it measures APCA Lc 49.0; on black, Lc -53.0. 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 18.2 and 17.5 and 17.2 — no red cone.

Text on this colour

White text

2.51:1 — fails AA

Black text

8.37:1 — passes AA

Black text is the better of the two at8.37:1. That is enough for body text.

As text on white, it needs to change

#207cbd is the nearest colour of the same hue that passes AA on white, at 4.50:1. Only the lightness moved.

Try it against your own background

The same colour, with one cone missing

As you see it

#55aaee

protanopia

#a3a3ee · ΔE00 18.2

deuteranopia

#9797ef · ΔE00 17.5

tritanopia

#8989ff · ΔE00 17.2

Run a whole palette through all three

The twelve nearest named colours

Ranked by CIEDE2000 — perceptual distance, not hex arithmetic. The closest isBlue Jeans at ΔE00 1.183: between 1 and 2 — a trained eye spots it when the two touch; nobody spots it across a room. What the numbers mean.

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