#42378A
Closest named color: Dark Slate Blue (#483D8B). oklch(39.7% 0.133 284.6), rgb(66, 55, 138).
Aa
White text reads best on this color (9.78:1).
About this color
#42378A is a dark, moderately saturated purple. In OKLCH its lightness is 40%, its chroma 0.133 and its hue 285°. Its hue sits on the cool side of the wheel. The nearest named color is Dark Slate Blue (#483D8B), ΔE 0.019 away. White text reads best on it, at 9.78:1.
| Hue family | Purples |
| Lightness | dark (40%) |
| Chroma | moderately saturated (0.133) |
| Temperature | cool |
| Nearest name | Dark Slate Blue (#483D8B) |
| Black text | 2.14:1 |
| White text | 9.78:1 |
Values
| HEX | #42378A |
| RGB | rgb(66, 55, 138) |
| HSL | hsl(248, 43%, 38%) |
| OKLCH | oklch(39.7% 0.133 284.6) |
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 #42378A | 9.78:1 | AAA | Lc -96.6 | Preferred for body text |
| Black text on #42378A | 2.14:1 | Fails | Lc 11.6 | Not readable |
| #42378A text on white | 9.78:1 | AAA | Lc 92.4 | Preferred for body text |
| #42378A text on black | 2.14:1 | Fails | Lc -10.1 | 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
#F4F4FE
oklch(97% 0.013 286.1)
-
Step 100
100
#E7E8FD
oklch(93.7% 0.028 283.7)
-
Step 200
200
#D4D5FD
oklch(88.5% 0.055 284.1)
-
Step 300
300
#B9B8FF
oklch(80.9% 0.1 284.6)
-
Step 400
400
#9790FF
oklch(70.8% 0.159 284.4)
-
Step 500
500
#816FFD
oklch(63.1% 0.203 284.7)
-
Step 600
600
#6D51EC
oklch(55.5% 0.221 284.9)
-
Step 700
700
#5B40CE
oklch(49% 0.207 284.5)
-
Step 800
800
#4A36A6
oklch(42.6% 0.171 284.7)
-
Step 900
900 (this color)
#42378A
oklch(39.7% 0.133 284.6)
-
Step 950
950
#231E4D
oklch(27% 0.084 284.1)
#42378A 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) | #00468D | 0.068 |
| Deuteranopia (no green cones) | #004188 | 0.066 |
| Tritanopia (no blue cones) | #274A5B | 0.111 |
| Achromatopsia (no color) | #444444 | 0.133 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #42378A
#42378A
oklch(39.7% 0.133 284.6)
- #4E4900
#4E4900
oklch(39.8% 0.084 105.1)
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 #42378A, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dark Slate Blue #483D8B ΔE 0.019
- Blueberry #464196 ΔE 0.032
- Cobalt #1E488F ΔE 0.058
- Sapphire #2138AB ΔE 0.070
- Rebecca Purple #663399 ΔE 0.070
- Twilight Blue #0A437A ΔE 0.072
- Twilight #4E518B ΔE 0.075
- Dusk Blue #26538D ΔE 0.078
Use #42378A 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.