Nocturne Blue
#37525f
A blue that is nearly neutral — the hue shows only against a true grey. It is mid — the hardest range to put text on, either colour struggles.
Hex
#37525f
RGB
55, 82, 95
OKLCh
42.2% 0.039 229.5°
CIELAB (D50)
33.1, -7.7, -11.0
What is true of this colour, and of no other
- 5 other named colours sit within ΔE00 2 of it.
- It uses 47% of the chroma sRGB can show at this lightness and hue.
- As text on white it measures APCA Lc 88.6; on black, Lc -13.6. 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 12.6 and 13.4 and 13.9 — no red cone.
Text on this colour
White text
8.29:1 — passes AA
Black text
2.53:1 — fails AA
White text is the better of the two at8.29:1. That is enough for body text.
The same colour, with one cone missing
As you see it
#37525f
protanopia
#4f4f5f · ΔE00 12.6
deuteranopia
#4b4b5f · ΔE00 13.4
tritanopia
#46468a · ΔE00 13.9
The twelve nearest named colours
Ranked by CIEDE2000 — perceptual distance, not hex arithmetic. The closest isOpera Glasses at ΔE00 0.648: below 1.0 — an ordinary observer cannot tell these apart, even side by side. What the numbers mean.
- Opera GlassesΔE00 0.648 · #365360
- Restless SeaΔE00 0.65 · #38515d
- Velvet EveningΔE00 0.947 · #33505e
- WentworthΔE00 1.122 · #345362
- NocturneΔE00 1.848 · #344d58
- SeaworthyΔE00 2.101 · #314d58
- Aircraft BlueΔE00 2.148 · #354f58
- StargazerΔE00 2.255 · #3f5865
- Celtic RushΔE00 2.331 · #2e4c5b
- Sailing SafariΔE00 2.338 · #3a5161
- Dark SecretΔE00 2.344 · #3e5361
- Mountain MidnightΔE00 2.36 · #385058
9 of these have no page of their own: pages exist for the 4,961 colours the dataset marks as good names.