#1B397B
Closest named color: Twilight Blue (#0A437A). oklch(36.3% 0.118 263.3), rgb(27, 57, 123).
Aa
White text reads best on this color (10.94:1).
About this color
#1B397B is a dark, moderately saturated blue. In OKLCH its lightness is 36%, its chroma 0.118 and its hue 263°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight Blue (#0A437A), ΔE 0.029 away. White text reads best on it, at 10.94:1.
| Hue family | Blues |
| Lightness | dark (36%) |
| Chroma | moderately saturated (0.118) |
| Temperature | cool |
| Nearest name | Twilight Blue (#0A437A) |
| Black text | 1.91:1 |
| White text | 10.94:1 |
Values
| HEX | #1B397B |
| RGB | rgb(27, 57, 123) |
| HSL | hsl(221, 64%, 29%) |
| OKLCH | oklch(36.3% 0.118 263.3) |
Contrast
WCAG 2 contrast ratios are the conformance target: AA needs 4.5:1 for body text and 3:1 for large text, AAA needs 7:1. APCA Lc values are supplementary guidance from the WCAG 3 drafts.
| Pair | WCAG 2 | Result | APCA | APCA guidance |
|---|---|---|---|---|
| White text on #1B397B | 10.94:1 | AAA | Lc -98.9 | Preferred for body text |
| Black text on #1B397B | 1.91:1 | Fails | Lc 9.0 | Not readable |
| #1B397B text on white | 10.94:1 | AAA | Lc 95.0 | Preferred for body text |
| #1B397B text on black | 1.91:1 | Fails | Lc -7.7 | Not readable |
Tints and shades
A 50–950 scale built in OKLCH: the hue is held, lightness follows a Tailwind v4-like curve, and every step is kept inside the sRGB gamut. This color sits at step 900.
-
Step 50
50
#F1F6FE
oklch(97.2% 0.012 259.8)
-
Step 100
100
#E1EAFC
oklch(93.6% 0.026 264.4)
-
Step 200
200
#C8DAFB
oklch(88.5% 0.05 262.6)
-
Step 300
300
#A3C1FB
oklch(81% 0.089 263.3)
-
Step 400
400
#719EF9
oklch(70.7% 0.143 263.3)
-
Step 500
500
#4D83F6
oklch(63.2% 0.182 263.2)
-
Step 600
600
#3269E4
oklch(55.6% 0.196 263.3)
-
Step 700
700
#2556C6
oklch(49% 0.183 263.4)
-
Step 800
800
#2047A0
oklch(42.6% 0.151 263.5)
-
Step 900
900 (this color)
#1B397B
oklch(36.3% 0.118 263.3)
-
Step 950
950
#12244B
oklch(26.9% 0.076 263.5)
#1B397B with color blindness
Simulated with the Machado et al. (2009) model. ΔE is how far the color moves: below about 0.02 you would not notice a change.
| Vision | Seen as | Shift (ΔE) |
|---|---|---|
| Protanopia (no red cones) | #0D417D | 0.023 |
| Deuteranopia (no green cones) | #00387A | 0.018 |
| Tritanopia (no blue cones) | #004954 | 0.093 |
| Achromatopsia (no color) | #3C3C3C | 0.118 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #1B397B
#1B397B
oklch(36.3% 0.118 263.3)
- #513A00
#513A00
oklch(36.5% 0.075 83.5)
Analogous
Neighbouring hues, 30° either side.
Split complementary
The two hues beside the complement (150° and 210°).
Triadic
Three hues spaced 120° apart.
Palettes with this color
Curated palettes that contain a color within ΔE 0.04 (OKLab) of #1B397B, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight Blue #0A437A ΔE 0.029
- Marine Blue #01386A ΔE 0.036
- Cobalt #1E488F ΔE 0.052
- Marine #042E60 ΔE 0.061
- Prussian Blue #1D3557 ΔE 0.062
- Light Navy #155084 ΔE 0.067
- Dark Slate Blue #483D8B ΔE 0.071
- Dark Grey Blue #29465B ΔE 0.076
Use #1B397B in your product
Turn it into light and dark UI roles checked for contrast, then export to Tailwind v4, shadcn/ui, CSS or design tokens.