#1B3589
Closest named color: Twilight Blue (#0A437A). oklch(36.6% 0.144 266.1), rgb(27, 53, 137).
Aa
White text reads best on this color (10.95:1).
About this color
#1B3589 is a dark, vivid blue. In OKLCH its lightness is 37%, its chroma 0.144 and its hue 266°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight Blue (#0A437A), ΔE 0.048 away. White text reads best on it, at 10.95:1.
| Hue family | Blues |
| Lightness | dark (37%) |
| Chroma | vivid (0.144) |
| Temperature | cool |
| Nearest name | Twilight Blue (#0A437A) |
| Black text | 1.91:1 |
| White text | 10.95:1 |
Values
| HEX | #1B3589 |
| RGB | rgb(27, 53, 137) |
| HSL | hsl(226, 67%, 32%) |
| OKLCH | oklch(36.6% 0.144 266.1) |
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 #1B3589 | 10.95:1 | AAA | Lc -98.7 | Preferred for body text |
| Black text on #1B3589 | 1.91:1 | Fails | Lc 9.1 | Not readable |
| #1B3589 text on white | 10.95:1 | AAA | Lc 94.8 | Preferred for body text |
| #1B3589 text on black | 1.91:1 | Fails | Lc -7.8 | 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
#E0EAFF
oklch(93.6% 0.03 265.3)
-
Step 200
200
#C8D9FF
oklch(88.5% 0.056 266.2)
-
Step 300
300
#A4C0FF
oklch(81% 0.095 265.8)
-
Step 400
400
#749CFF
oklch(70.8% 0.152 266)
-
Step 500
500
#517FFF
oklch(63.2% 0.197 266)
-
Step 600
600
#325EFC
oklch(55.5% 0.239 266.2)
-
Step 700
700
#264CDC
oklch(49.1% 0.223 266.1)
-
Step 800
800
#2040B2
oklch(42.8% 0.184 266.2)
-
Step 900
900 (this color)
#1B3589
oklch(36.6% 0.144 266.1)
-
Step 950
950
#112252
oklch(27% 0.091 265.8)
#1B3589 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) | #00428C | 0.034 |
| Deuteranopia (no green cones) | #003887 | 0.017 |
| Tritanopia (no blue cones) | #004A59 | 0.112 |
| Achromatopsia (no color) | #3C3C3C | 0.144 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #1B3589
#1B3589
oklch(36.6% 0.144 266.1)
- #503B00
#503B00
oklch(36.6% 0.075 86)
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 #1B3589, closest first.
No curated palette has a color within ΔE 0.04 of #1B3589.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight Blue #0A437A ΔE 0.048
- Cobalt #1E488F ΔE 0.052
- Sapphire #2138AB ΔE 0.058
- Marine Blue #01386A ΔE 0.058
- Royal #0C1793 ΔE 0.065
- Dark Slate Blue #483D8B ΔE 0.069
- Blueberry #464196 ΔE 0.073
- Light Navy #155084 ΔE 0.077
Use #1B3589 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.