#1B3B79
Closest named color: Twilight Blue (#0A437A). oklch(36.6% 0.113 261.9), rgb(27, 59, 121).
Aa
White text reads best on this color (10.77:1).
About this color
#1B3B79 is a dark, moderately saturated blue. In OKLCH its lightness is 37%, its chroma 0.113 and its hue 262°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight Blue (#0A437A), ΔE 0.024 away. White text reads best on it, at 10.77:1.
| Hue family | Blues |
| Lightness | dark (37%) |
| Chroma | moderately saturated (0.113) |
| Temperature | cool |
| Nearest name | Twilight Blue (#0A437A) |
| Black text | 1.94:1 |
| White text | 10.77:1 |
Values
| HEX | #1B3B79 |
| RGB | rgb(27, 59, 121) |
| HSL | hsl(220, 64%, 29%) |
| OKLCH | oklch(36.6% 0.113 261.9) |
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 #1B3B79 | 10.77:1 | AAA | Lc -98.6 | Preferred for body text |
| Black text on #1B3B79 | 1.94:1 | Fails | Lc 9.3 | Not readable |
| #1B3B79 text on white | 10.77:1 | AAA | Lc 94.6 | Preferred for body text |
| #1B3B79 text on black | 1.94:1 | Fails | Lc -8.0 | 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
#F1F6FD
oklch(97.1% 0.011 256.7)
-
Step 100
100
#E1EAFB
oklch(93.5% 0.025 263.3)
-
Step 200
200
#C8DAF9
oklch(88.5% 0.047 261.4)
-
Step 300
300
#A3C1F8
oklch(80.8% 0.085 262.3)
-
Step 400
400
#719FF4
oklch(70.6% 0.135 261.9)
-
Step 500
500
#4C85F0
oklch(63.2% 0.172 261.7)
-
Step 600
600
#306BDF
oklch(55.6% 0.188 262)
-
Step 700
700
#2359C2
oklch(49.2% 0.174 261.9)
-
Step 800
800
#1E499D
oklch(42.7% 0.145 261.9)
-
Step 900
900 (this color)
#1B3B79
oklch(36.6% 0.113 261.9)
-
Step 950
950
#122549
oklch(27% 0.071 261.9)
#1B3B79 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) | #17427B | 0.020 |
| Deuteranopia (no green cones) | #003978 | 0.019 |
| Tritanopia (no blue cones) | #004A54 | 0.089 |
| Achromatopsia (no color) | #3D3D3D | 0.113 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #1B3B79
#1B3B79
oklch(36.6% 0.113 261.9)
- #523A00
#523A00
oklch(36.6% 0.075 82.4)
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 #1B3B79, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight Blue #0A437A ΔE 0.024
- Marine Blue #01386A ΔE 0.034
- Cobalt #1E488F ΔE 0.050
- Prussian Blue #1D3557 ΔE 0.059
- Marine #042E60 ΔE 0.062
- Light Navy #155084 ΔE 0.062
- Dark Grey Blue #29465B ΔE 0.070
- Dark Slate Blue #483D8B ΔE 0.070
Use #1B3B79 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.