#1B4288
Closest named color: Cobalt (#1E488F). oklch(39.4% 0.125 261), rgb(27, 66, 136).
Aa
White text reads best on this color (9.62:1).
About this color
#1B4288 is a dark, moderately saturated blue. In OKLCH its lightness is 39%, its chroma 0.125 and its hue 261°. Its hue sits on the cool side of the wheel. The nearest named color is Cobalt (#1E488F), ΔE 0.020 away. White text reads best on it, at 9.62:1.
| Hue family | Blues |
| Lightness | dark (39%) |
| Chroma | moderately saturated (0.125) |
| Temperature | cool |
| Nearest name | Cobalt (#1E488F) |
| Black text | 2.18:1 |
| White text | 9.62:1 |
Values
| HEX | #1B4288 |
| RGB | rgb(27, 66, 136) |
| HSL | hsl(219, 67%, 32%) |
| OKLCH | oklch(39.4% 0.125 261) |
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 #1B4288 | 9.62:1 | AAA | Lc -96.1 | Preferred for body text |
| Black text on #1B4288 | 2.18:1 | Fails | Lc 12.1 | Not readable |
| #1B4288 text on white | 9.62:1 | AAA | Lc 91.9 | Preferred for body text |
| #1B4288 text on black | 2.18:1 | Fails | Lc -10.5 | 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
#E0EBFD
oklch(93.7% 0.027 260.3)
-
Step 200
200
#C6DAFC
oklch(88.4% 0.052 261.1)
-
Step 300
300
#9EC2FE
oklch(81% 0.094 260.4)
-
Step 400
400
#699FFD
oklch(70.7% 0.15 260.8)
-
Step 500
500
#4083FB
oklch(63% 0.192 261)
-
Step 600
600
#1F69EB
oklch(55.6% 0.209 261)
-
Step 700
700
#1256CC
oklch(49% 0.194 261.1)
-
Step 800
800
#1247A5
oklch(42.6% 0.161 261.1)
-
Step 900
900 (this color)
#1B4288
oklch(39.4% 0.125 261)
-
Step 950
950
#0E244D
oklch(26.9% 0.081 261.5)
#1B4288 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) | #174A8B | 0.022 |
| Deuteranopia (no green cones) | #004087 | 0.017 |
| Tritanopia (no blue cones) | #00535E | 0.098 |
| Achromatopsia (no color) | #454545 | 0.125 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #1B4288
#1B4288
oklch(39.4% 0.125 261)
- #5C4000
#5C4000
oklch(39.3% 0.081 80.5)
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 #1B4288, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cobalt #1E488F ΔE 0.020
- Twilight Blue #0A437A ΔE 0.027
- Light Navy #155084 ΔE 0.042
- Dusk Blue #26538D ΔE 0.052
- Deep Sea Blue #015482 ΔE 0.055
- Dark Slate Blue #483D8B ΔE 0.058
- Blueberry #464196 ΔE 0.059
- Marine Blue #01386A ΔE 0.062
Use #1B4288 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.