International Klein Blue
#002fa6
A blue that is saturated. It is dark — it carries white text and needs care with black.
Hex
#002fa6
RGB
0, 47, 166
OKLCh
37.7% 0.194 263.2°
CIELAB (D50)
24.8, 28.2, -68.3
What is true of this colour, and of no other
- 4 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 93.6; on black, Lc -8.9. 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.
- tritanopia shifts it by ΔE00 5.3 — no blue cone.
Text on this colour
White text
10.73:1 — passes AA
Black text
1.96:1 — fails AA
White text is the better of the two at10.73:1. That is enough for body text.
The same colour, with one cone missing
As you see it
#002fa6
protanopia
#2c2ca6 · ΔE00 3.9
deuteranopia
#2727a6 · ΔE00 4.2
tritanopia
#2020b6 · ΔE00 5.3
The twelve nearest named colours
Ranked by CIEDE2000 — perceptual distance, not hex arithmetic. The closest isInternational Blue at ΔE00 0.125: below 1.0 — an ordinary observer cannot tell these apart, even side by side. What the numbers mean.
- International BlueΔE00 0.125 · #002fa7
- UA BlueΔE00 1.274 · #0033aa
- Egyptian BlueΔE00 1.398 · #1034a6
- Blue HourΔE00 1.596 · #0034ab
- SmaltΔE00 2.249 · #003399
- North Star BlueΔE00 2.484 · #223399
- Blue Screen of DeathΔE00 2.736 · #0033bb
- Royal AzureΔE00 2.834 · #0038a8
- Yuè Guāng Lán BlueΔE00 2.836 · #2138ab
- Philippine BlueΔE00 2.849 · #0038a7
- Blue TorusΔE00 2.852 · #042993
- US Air Force BlueΔE00 3.017 · #00308f
9 of these have no page of their own: pages exist for the 4,961 colours the dataset marks as good names.