Blue Hour
#0034ab
A blue that is saturated. It is dark — it carries white text and needs care with black.
Hex
#0034ab
RGB
0, 52, 171
OKLCh
39.1% 0.195 262.9°
CIELAB (D50)
26.5, 26.7, -68.5
What is true of this colour, and of no other
- 8 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 92.2; on black, Lc -10.2. 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 6.0 — no blue cone.
Text on this colour
White text
10.10:1 — passes AA
Black text
2.08:1 — fails AA
White text is the better of the two at10.10:1. That is enough for body text.
The same colour, with one cone missing
As you see it
#0034ab
protanopia
#3131ab · ΔE00 4.5
deuteranopia
#2b2bab · ΔE00 4.8
tritanopia
#2424bd · ΔE00 6.0
The twelve nearest named colours
Ranked by CIEDE2000 — perceptual distance, not hex arithmetic. The closest isUA Blue at ΔE00 0.321: below 1.0 — an ordinary observer cannot tell these apart, even side by side. What the numbers mean.
- UA BlueΔE00 0.321 · #0033aa
- Egyptian BlueΔE00 0.791 · #1034a6
- Royal AzureΔE00 1.391 · #0038a8
- Philippine BlueΔE00 1.449 · #0038a7
- International BlueΔE00 1.565 · #002fa7
- International Klein BlueΔE00 1.596 · #002fa6
- Yuè Guāng Lán BlueΔE00 1.942 · #2138ab
- Blue Screen of DeathΔE00 1.993 · #0033bb
- SmaltΔE00 2.227 · #003399
- Persian BlueΔE00 2.815 · #1c39bb
- North Star BlueΔE00 2.971 · #223399
- Dark Seashore NightΔE00 3.146 · #113691
9 of these have no page of their own: pages exist for the 4,961 colours the dataset marks as good names.