Burning Ultrablue

#150aec

A blue that is about as vivid as sRGB can show at this lightness. It is mid — the hardest range to put text on, either colour struggles.

Hex

#150aec

RGB

21, 10, 236

OKLCh

43.4% 0.290 266.0°

CIELAB (D50)

28.0, 62.9, -103.9

What is true of this colour, and of no other

  • 11 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 98% 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 88.2; on black, Lc -14.0. 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.
  • All three dichromacies see it as very nearly the same colour you do: its hue is not the part carrying its identity.

Text on this colour

White text

9.18:1 — passes AA

Black text

2.29:1 — fails AA

White text is the better of the two at9.18:1. That is enough for body text.

The same colour, with one cone missing

As you see it

#150aec

protanopia

#0c0cec · ΔE00 0.3

deuteranopia

#0e0eec · ΔE00 0.4

tritanopia

#1010ea · ΔE00 0.5

Run a whole palette through all three

The twelve nearest named colours

Ranked by CIEDE2000 — perceptual distance, not hex arithmetic. The closest isHyperlink Blue at ΔE00 0.739: below 1.0 — an ordinary observer cannot tell these apart, even side by side. What the numbers mean.

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