#1B3387
Closest named color: Twilight Blue (#0A437A). oklch(36.1% 0.143 266.6), rgb(27, 51, 135).
Aa
White text reads best on this color (11.23:1).
About this color
#1B3387 is a dark, vivid blue. In OKLCH its lightness is 36%, its chroma 0.143 and its hue 267°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight Blue (#0A437A), ΔE 0.050 away. White text reads best on it, at 11.23:1.
| Hue family | Blues |
| Lightness | dark (36%) |
| Chroma | vivid (0.143) |
| Temperature | cool |
| Nearest name | Twilight Blue (#0A437A) |
| Black text | 1.86:1 |
| White text | 11.23:1 |
Values
| HEX | #1B3387 |
| RGB | rgb(27, 51, 135) |
| HSL | hsl(227, 67%, 32%) |
| OKLCH | oklch(36.1% 0.143 266.6) |
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 #1B3387 | 11.23:1 | AAA | Lc -99.2 | Preferred for body text |
| Black text on #1B3387 | 1.86:1 | Fails | Lc 8.5 | Not readable |
| #1B3387 text on white | 11.23:1 | AAA | Lc 95.4 | Preferred for body text |
| #1B3387 text on black | 1.86:1 | Fails | Lc 0.0 | 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
#F1F5FF
oklch(97% 0.014 268.5)
-
Step 100
100
#E1EAFF
oklch(93.7% 0.03 267.2)
-
Step 200
200
#C8D9FF
oklch(88.5% 0.056 266.2)
-
Step 300
300
#A5BFFF
oklch(80.9% 0.095 267.2)
-
Step 400
400
#759BFF
oklch(70.6% 0.153 266.8)
-
Step 500
500
#537EFF
oklch(63.1% 0.197 266.8)
-
Step 600
600
#345EFC
oklch(55.6% 0.239 266.6)
-
Step 700
700
#284CDC
oklch(49.2% 0.222 266.5)
-
Step 800
800
#223FB2
oklch(42.7% 0.185 266.8)
-
Step 900
900 (this color)
#1B3387
oklch(36.1% 0.143 266.6)
-
Step 950
950
#122252
oklch(27.1% 0.09 266.4)
#1B3387 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) | #00408A | 0.034 |
| Deuteranopia (no green cones) | #003685 | 0.018 |
| Tritanopia (no blue cones) | #004958 | 0.113 |
| Achromatopsia (no color) | #3B3B3B | 0.144 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #1B3387
#1B3387
oklch(36.1% 0.143 266.6)
- #4E3A00
#4E3A00
oklch(36.1% 0.074 86.8)
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 #1B3387, closest first.
No curated palette has a color within ΔE 0.04 of #1B3387.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight Blue #0A437A ΔE 0.050
- Marine Blue #01386A ΔE 0.056
- Cobalt #1E488F ΔE 0.058
- Royal #0C1793 ΔE 0.062
- Sapphire #2138AB ΔE 0.062
- Dark Slate Blue #483D8B ΔE 0.073
- Marine #042E60 ΔE 0.073
- Midnight Blue #191970 ΔE 0.074
Use #1B3387 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.