#1F3188
Closest named color: Twilight Blue (#0A437A). oklch(35.9% 0.146 268.7), rgb(31, 49, 136).
Aa
White text reads best on this color (11.33:1).
About this color
#1F3188 is a dark, vivid blue. In OKLCH its lightness is 36%, its chroma 0.146 and its hue 269°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight Blue (#0A437A), ΔE 0.056 away. White text reads best on it, at 11.33:1.
| Hue family | Blues |
| Lightness | dark (36%) |
| Chroma | vivid (0.146) |
| Temperature | cool |
| Nearest name | Twilight Blue (#0A437A) |
| Black text | 1.85:1 |
| White text | 11.33:1 |
Values
| HEX | #1F3188 |
| RGB | rgb(31, 49, 136) |
| HSL | hsl(230, 63%, 33%) |
| OKLCH | oklch(35.9% 0.146 268.7) |
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 #1F3188 | 11.33:1 | AAA | Lc -99.4 | Preferred for body text |
| Black text on #1F3188 | 1.85:1 | Fails | Lc 8.3 | Not readable |
| #1F3188 text on white | 11.33:1 | AAA | Lc 95.6 | Preferred for body text |
| #1F3188 text on black | 1.85:1 | 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
#CAD8FF
oklch(88.4% 0.056 269.7)
-
Step 300
300
#A7BFFF
oklch(81% 0.095 268.4)
-
Step 400
400
#799AFF
oklch(70.6% 0.153 268.6)
-
Step 500
500
#597DFF
oklch(63.2% 0.197 268.6)
-
Step 600
600
#3D5BFF
oklch(55.7% 0.244 268.6)
-
Step 700
700
#3048DE
oklch(49% 0.227 268.6)
-
Step 800
800
#283DB3
oklch(42.7% 0.187 268.8)
-
Step 900
900 (this color)
#1F3188
oklch(35.9% 0.146 268.7)
-
Step 950
950
#142153
oklch(27% 0.093 268.5)
#1F3188 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) | #003F8B | 0.037 |
| Deuteranopia (no green cones) | #003586 | 0.022 |
| Tritanopia (no blue cones) | #004757 | 0.115 |
| Achromatopsia (no color) | #3A3A3A | 0.147 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #1F3188
#1F3188
oklch(35.9% 0.146 268.7)
- #4D3A00
#4D3A00
oklch(35.9% 0.073 87.9)
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 #1F3188, closest first.
No curated palette has a color within ΔE 0.04 of #1F3188.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight Blue #0A437A ΔE 0.056
- Royal #0C1793 ΔE 0.059
- Marine Blue #01386A ΔE 0.060
- Sapphire #2138AB ΔE 0.061
- Cobalt #1E488F ΔE 0.061
- Dark Slate Blue #483D8B ΔE 0.072
- Midnight Blue #191970 ΔE 0.072
- Marine #042E60 ΔE 0.075
Use #1F3188 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.