#283F42
Closest named color: Onyx (#343A40). oklch(35% 0.029 206.2), rgb(40, 63, 66).
Aa
White text reads best on this color (11.17:1).
About this color
#283F42 is a dark close to neutral grey. In OKLCH its lightness is 35%, its chroma 0.029. It has too little chroma to lean warm or cool. The nearest named color is Onyx (#343A40), ΔE 0.022 away. White text reads best on it, at 11.17:1.
| Hue family | Neutrals |
| Lightness | dark (35%) |
| Chroma | close to neutral grey (0.029) |
| Temperature | neutral |
| Nearest name | Onyx (#343A40) |
| Black text | 1.87:1 |
| White text | 11.17:1 |
Values
| HEX | #283F42 |
| RGB | rgb(40, 63, 66) |
| HSL | hsl(187, 25%, 21%) |
| OKLCH | oklch(35% 0.029 206.2) |
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 #283F42 | 11.17:1 | AAA | Lc -99.6 | Preferred for body text |
| Black text on #283F42 | 1.87:1 | Fails | Lc 8.1 | Not readable |
| #283F42 text on white | 11.17:1 | AAA | Lc 95.8 | Preferred for body text |
| #283F42 text on black | 1.87:1 | 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
#F3F6F6
oklch(97.1% 0.003 197.1)
-
Step 100
100
#E5EBEC
oklch(93.6% 0.007 208.8)
-
Step 200
200
#D0DCDD
oklch(88.6% 0.013 202.9)
-
Step 300
300
#B1C5C7
oklch(80.9% 0.022 204)
-
Step 400
400
#88A7AB
oklch(70.6% 0.035 206)
-
Step 500
500
#6A9297
oklch(63.2% 0.045 205.7)
-
Step 600
600
#507C81
oklch(55.6% 0.049 204.9)
-
Step 700
700
#41686D
oklch(49% 0.045 206.1)
-
Step 800
800
#365559
oklch(42.7% 0.037 206.1)
-
Step 900
900 (this color)
#283F42
oklch(35% 0.029 206.2)
-
Step 950
950
#1C292B
oklch(27% 0.018 207.9)
#283F42 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) | #3B3D42 | 0.028 |
| Deuteranopia (no green cones) | #373A42 | 0.026 |
| Tritanopia (no blue cones) | #1E4140 | 0.014 |
| Achromatopsia (no color) | #3B3B3B | 0.029 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #283F42
#283F42
oklch(35% 0.029 206.2)
- #493532
#493532
oklch(35.1% 0.029 28.4)
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 #283F42, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Onyx #343A40 ΔE 0.022
- Dark Blue Grey #1F3B4D ΔE 0.029
- Charcoal Grey #3C4142 ΔE 0.031
- Charcoal #264653 ΔE 0.032
- Midnight Green #073B4C ΔE 0.039
- Gunmetal #293241 ΔE 0.044
- Dark Grey Blue #29465B ΔE 0.044
- Dark Teal #014D4E ΔE 0.048
Use #283F42 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.