#283B88
Closest named color: Cobalt (#1E488F). oklch(38.4% 0.131 269), rgb(40, 59, 136).
Aa
White text reads best on this color (10.13:1).
About this color
#283B88 is a dark, moderately saturated blue. In OKLCH its lightness is 38%, its chroma 0.131 and its hue 269°. Its hue sits on the cool side of the wheel. The nearest named color is Cobalt (#1E488F), ΔE 0.036 away. White text reads best on it, at 10.13:1.
| Hue family | Blues |
| Lightness | dark (38%) |
| Chroma | moderately saturated (0.131) |
| Temperature | cool |
| Nearest name | Cobalt (#1E488F) |
| Black text | 2.07:1 |
| White text | 10.13:1 |
Values
| HEX | #283B88 |
| RGB | rgb(40, 59, 136) |
| HSL | hsl(228, 55%, 35%) |
| OKLCH | oklch(38.4% 0.131 269) |
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 #283B88 | 10.13:1 | AAA | Lc -97.3 | Preferred for body text |
| Black text on #283B88 | 2.07:1 | Fails | Lc 10.8 | Not readable |
| #283B88 text on white | 10.13:1 | AAA | Lc 93.2 | Preferred for body text |
| #283B88 text on black | 2.07:1 | Fails | Lc -9.3 | 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
#F2F5FF
oklch(97.1% 0.014 272.7)
-
Step 100
100
#E2EAFE
oklch(93.7% 0.028 268.4)
-
Step 200
200
#CAD8FE
oklch(88.4% 0.055 269.3)
-
Step 300
300
#A7BEFF
oklch(80.8% 0.096 269.2)
-
Step 400
400
#7A9AFF
oklch(70.7% 0.152 269)
-
Step 500
500
#5A7CFF
oklch(63% 0.198 269.1)
-
Step 600
600
#4260F0
oklch(55.5% 0.218 269)
-
Step 700
700
#354ED1
oklch(49% 0.203 269)
-
Step 800
800
#2C41A9
oklch(42.7% 0.168 269.2)
-
Step 900
900 (this color)
#283B88
oklch(38.4% 0.131 269)
-
Step 950
950
#16224E
oklch(26.9% 0.083 268.8)
#283B88 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) | #00468B | 0.036 |
| Deuteranopia (no green cones) | #003D86 | 0.029 |
| Tritanopia (no blue cones) | #004E5B | 0.108 |
| Achromatopsia (no color) | #414141 | 0.131 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #283B88
#283B88
oklch(38.4% 0.131 269)
- #544100
#544100
oklch(38.5% 0.079 89.8)
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 #283B88, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cobalt #1E488F ΔE 0.036
- Twilight Blue #0A437A ΔE 0.040
- Dark Slate Blue #483D8B ΔE 0.049
- Blueberry #464196 ΔE 0.053
- Sapphire #2138AB ΔE 0.058
- Light Navy #155084 ΔE 0.060
- Marine Blue #01386A ΔE 0.063
- Dusk Blue #26538D ΔE 0.067
Use #283B88 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.