Gentian Blue
#312297
A blue that is saturated. It is dark — it carries white text and needs care with black.
Hex
#312297
RGB
49, 34, 151
OKLCh
36.1% 0.178 278.4°
CIELAB (D50)
22.7, 35.6, -62.6
What is true of this colour, and of no other
- No other named colour in the set is within ΔE00 2 of it — it stands alone.
- It uses 81% of the chroma sRGB can show at this lightness and hue.
- As text on white it measures APCA Lc 95.8; on black, Lc 0.0. 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.
- All three dichromacies see it as very nearly the same colour you do: its hue is not the part carrying its identity.
Text on this colour
White text
11.63:1 — passes AA
Black text
1.81:1 — fails AA
White text is the better of the two at11.63:1. That is enough for body text.
The same colour, with one cone missing
As you see it
#312297
protanopia
#242497 · ΔE00 2.1
deuteranopia
#272797 · ΔE00 2.3
tritanopia
#2a2a8d · ΔE00 3.1
The twelve nearest named colours
Ranked by CIEDE2000 — perceptual distance, not hex arithmetic. The closest isIndiglow at ΔE00 3.544: between 2 and 5 — clearly two colours when compared, easily mistaken from memory. What the numbers mean.
- IndiglowΔE00 3.544 · #301885
- Deep Daijin BlueΔE00 3.716 · #3311aa
- Cosmic CobaltΔE00 3.904 · #2e2d88
- Indigo BlueΔE00 3.911 · #3a18b1
- RoyalΔE00 4.001 · #0c1793
- Celestial IndigoΔE00 4.071 · #091f92
- Nightly ExpeditionΔE00 4.243 · #221188
- Blue RoyaleΔE00 4.307 · #29217a
- Bright MidnightΔE00 4.351 · #011993
- Galactic PurpleΔE00 4.372 · #472e97
- Dark GalaxyΔE00 4.373 · #0018a8
- Depths of NightΔE00 4.499 · #2c319b
6 of these have no page of their own: pages exist for the 4,961 colours the dataset marks as good names.