Dark Crypt
#3f4551
A neutral that has no useful hue — it reads as a grey. It is dark — it carries white text and needs care with black.
Hex
#3f4551
RGB
63, 69, 81
OKLCh
39.0% 0.022 264.3°
CIELAB (D50)
29.1, -0.3, -8.1
What is true of this colour, and of no other
- 12 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 only 8% of the chroma available at this lightness and hue — there is a far more vivid version of this colour inside sRGB.
- As text on white it measures APCA Lc 92.3; on black, Lc -10.1. 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 8.1 — no blue cone.
Text on this colour
White text
9.63:1 — passes AA
Black text
2.18:1 — fails AA
White text is the better of the two at9.63:1. That is enough for body text.
The same colour, with one cone missing
As you see it
#3f4551
protanopia
#444451 · ΔE00 3.6
deuteranopia
#434351 · ΔE00 3.8
tritanopia
#42425e · ΔE00 8.1
The twelve nearest named colours
Ranked by CIEDE2000 — perceptual distance, not hex arithmetic. The closest isMidnight Sky at ΔE00 0.919: below 1.0 — an ordinary observer cannot tell these apart, even side by side. What the numbers mean.
- Midnight SkyΔE00 0.919 · #424753
- Bank BlueΔE00 1.077 · #3e4652
- Blue AshΔE00 1.37 · #414654
- Soft SteelΔE00 1.372 · #404854
- RhinoΔE00 1.448 · #3d4653
- Boeing BlueΔE00 1.568 · #3d4652
- Meteorite Black BlueΔE00 1.645 · #414756
- Whispered SecretΔE00 1.657 · #3f4855
- Astrogranite DebrisΔE00 1.728 · #3b424c
- Blue Sou’westerΔE00 1.846 · #404956
- Pit StopΔE00 1.913 · #414958
- InkblotΔE00 1.989 · #393f4b
10 of these have no page of their own: pages exist for the 4,961 colours the dataset marks as good names.