Blue Screen of Death
#0033bb
A blue that is saturated. It is mid — the hardest range to put text on, either colour struggles.
Hex
#0033bb
RGB
0, 51, 187
OKLCh
40.7% 0.215 263.4°
CIELAB (D50)
27.8, 32.7, -75.9
What is true of this colour, and of no other
- 2 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 90.8; on black, Lc -11.5. 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 5.1 — no blue cone.
Text on this colour
White text
9.58:1 — passes AA
Black text
2.19:1 — fails AA
White text is the better of the two at9.58:1. That is enough for body text.
The same colour, with one cone missing
As you see it
#0033bb
protanopia
#3030bb · ΔE00 3.7
deuteranopia
#2a2abb · ΔE00 4.0
tritanopia
#2323cb · ΔE00 5.1
The twelve nearest named colours
Ranked by CIEDE2000 — perceptual distance, not hex arithmetic. The closest isPersian Blue at ΔE00 1.769: between 1 and 2 — a trained eye spots it when the two touch; nobody spots it across a room. What the numbers mean.
- Persian BlueΔE00 1.769 · #1c39bb
- Blue HourΔE00 1.993 · #0034ab
- Sapphire GlitterΔE00 2.001 · #0033cc
- UA BlueΔE00 2.067 · #0033aa
- Yuè Guāng Lán BlueΔE00 2.33 · #2138ab
- Blue MurderΔE00 2.366 · #2539bf
- Egyptian BlueΔE00 2.411 · #1034a6
- International BlueΔE00 2.626 · #002fa7
- International Klein BlueΔE00 2.736 · #002fa6
- Royal AzureΔE00 2.917 · #0038a8
- Philippine BlueΔE00 3.026 · #0038a7
- Blue Cardinal FlowerΔE00 3.027 · #2f36ba
9 of these have no page of their own: pages exist for the 4,961 colours the dataset marks as good names.