#42537D
Closest named color: Dusk (#4E5481). oklch(44.7% 0.073 266.7), rgb(66, 83, 125).
Aa
White text reads best on this color (7.59:1).
About this color
#42537D is a dark, moderately saturated blue. In OKLCH its lightness is 45%, its chroma 0.073 and its hue 267°. Its hue sits on the cool side of the wheel. The nearest named color is Dusk (#4E5481), ΔE 0.019 away. White text reads best on it, at 7.59:1.
| Hue family | Blues |
| Lightness | dark (45%) |
| Chroma | moderately saturated (0.073) |
| Temperature | cool |
| Nearest name | Dusk (#4E5481) |
| Black text | 2.76:1 |
| White text | 7.59:1 |
Values
| HEX | #42537D |
| RGB | rgb(66, 83, 125) |
| HSL | hsl(223, 31%, 37%) |
| OKLCH | oklch(44.7% 0.073 266.7) |
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 #42537D | 7.59:1 | AAA | Lc -91.1 | Preferred for body text |
| Black text on #42537D | 2.76:1 | Fails | Lc 17.7 | Dividers and decoration only |
| #42537D text on white | 7.59:1 | AAA | Lc 86.3 | Fine for body text |
| #42537D text on black | 2.76:1 | Fails | Lc -15.7 | Dividers and decoration only |
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 800.
-
Step 50
50
#F4F5F9
oklch(97.1% 0.005 275)
-
Step 100
100
#E6EAF2
oklch(93.6% 0.012 264.5)
-
Step 200
200
#D2D9E9
oklch(88.5% 0.023 266.9)
-
Step 300
300
#B4C1DD
oklch(81% 0.042 265.7)
-
Step 400
400
#8DA0CC
oklch(70.7% 0.068 266.5)
-
Step 500
500
#7188BF
oklch(63.1% 0.088 266.5)
-
Step 600
600
#5A71AB
oklch(55.6% 0.095 266.9)
-
Step 700
700
#4A5F93
oklch(49.2% 0.088 266.5)
-
Step 800
800 (this color)
#42537D
oklch(44.7% 0.073 266.7)
-
Step 900
900
#344160
oklch(37.8% 0.056 266.4)
-
Step 950
950
#1E2638
oklch(27% 0.036 265.6)
#42537D 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) | #44577F | 0.012 |
| Deuteranopia (no green cones) | #3E517C | 0.009 |
| Tritanopia (no blue cones) | #2C5C62 | 0.066 |
| Achromatopsia (no color) | #545454 | 0.073 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #42537D
#42537D
oklch(44.7% 0.073 266.7)
- #66521F
#66521F
oklch(44.8% 0.073 87.5)
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 #42537D, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dusk #4E5481 ΔE 0.019
- YInMn Blue #415A77 ΔE 0.026
- Light Navy Blue #2E5A88 ΔE 0.030
- Twilight #4E518B ΔE 0.031
- Dusty Grape #545775 ΔE 0.033
- Denim Blue #3B5B92 ΔE 0.037
- Dusk Blue #26538D ΔE 0.039
- Dusky Blue #475F94 ΔE 0.047
Use #42537D 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.