#1F3388
Closest named color: Twilight Blue (#0A437A). oklch(36.3% 0.144 268.1), rgb(31, 51, 136).
Aa
White text reads best on this color (11.12:1).
About this color
#1F3388 is a dark, vivid blue. In OKLCH its lightness is 36%, its chroma 0.144 and its hue 268°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight Blue (#0A437A), ΔE 0.052 away. White text reads best on it, at 11.12:1.
| Hue family | Blues |
| Lightness | dark (36%) |
| Chroma | vivid (0.144) |
| Temperature | cool |
| Nearest name | Twilight Blue (#0A437A) |
| Black text | 1.88:1 |
| White text | 11.12:1 |
Values
| HEX | #1F3388 |
| RGB | rgb(31, 51, 136) |
| HSL | hsl(229, 63%, 33%) |
| OKLCH | oklch(36.3% 0.144 268.1) |
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 #1F3388 | 11.12:1 | AAA | Lc -99.0 | Preferred for body text |
| Black text on #1F3388 | 1.88:1 | Fails | Lc 8.7 | Not readable |
| #1F3388 text on white | 11.12:1 | AAA | Lc 95.2 | Preferred for body text |
| #1F3388 text on black | 1.88:1 | Fails | Lc -7.5 | 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
#F1F5FF
oklch(97% 0.014 268.5)
-
Step 100
100
#E1EAFF
oklch(93.7% 0.03 267.2)
-
Step 200
200
#C9D9FF
oklch(88.6% 0.055 267.2)
-
Step 300
300
#A6BFFF
oklch(80.9% 0.095 267.8)
-
Step 400
400
#789BFF
oklch(70.8% 0.152 267.9)
-
Step 500
500
#577DFF
oklch(63.1% 0.197 268)
-
Step 600
600
#3B5CFC
oklch(55.5% 0.239 268.1)
-
Step 700
700
#2F4ADC
oklch(49.1% 0.223 268.2)
-
Step 800
800
#263EB2
oklch(42.7% 0.185 268)
-
Step 900
900 (this color)
#1F3388
oklch(36.3% 0.144 268.1)
-
Step 950
950
#142152
oklch(26.9% 0.091 268.4)
#1F3388 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) | #00408B | 0.035 |
| Deuteranopia (no green cones) | #003786 | 0.022 |
| Tritanopia (no blue cones) | #004958 | 0.114 |
| Achromatopsia (no color) | #3B3B3B | 0.144 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #1F3388
#1F3388
oklch(36.3% 0.144 268.1)
- #4E3B00
#4E3B00
oklch(36.3% 0.074 88.2)
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 #1F3388, closest first.
No curated palette has a color within ΔE 0.04 of #1F3388.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight Blue #0A437A ΔE 0.052
- Cobalt #1E488F ΔE 0.057
- Marine Blue #01386A ΔE 0.059
- Sapphire #2138AB ΔE 0.060
- Royal #0C1793 ΔE 0.064
- Dark Slate Blue #483D8B ΔE 0.069
- Blueberry #464196 ΔE 0.074
- Marine #042E60 ΔE 0.076
Use #1F3388 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.