#42539B
Closest named color: Twilight (#4E518B). oklch(46.5% 0.118 271.2), rgb(66, 83, 155).
Aa
White text reads best on this color (7.13:1).
About this color
#42539B is a medium-dark, moderately saturated blue. In OKLCH its lightness is 47%, its chroma 0.118 and its hue 271°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight (#4E518B), ΔE 0.030 away. White text reads best on it, at 7.13:1.
| Hue family | Blues |
| Lightness | medium-dark (47%) |
| Chroma | moderately saturated (0.118) |
| Temperature | cool |
| Nearest name | Twilight (#4E518B) |
| Black text | 2.94:1 |
| White text | 7.13:1 |
Values
| HEX | #42539B |
| RGB | rgb(66, 83, 155) |
| HSL | hsl(229, 40%, 43%) |
| OKLCH | oklch(46.5% 0.118 271.2) |
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 #42539B | 7.13:1 | AAA | Lc -89.5 | Fine for body text |
| Black text on #42539B | 2.94:1 | Fails | Lc 19.5 | Dividers and decoration only |
| #42539B text on white | 7.13:1 | AAA | Lc 84.6 | Fine for body text |
| #42539B text on black | 2.94:1 | Fails | Lc -17.4 | 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 700.
-
Step 50
50
#F3F5FB
oklch(97% 0.008 271.3)
-
Step 100
100
#E6EAF5
oklch(93.7% 0.015 270)
-
Step 200
200
#D1D9EF
oklch(88.6% 0.031 269.8)
-
Step 300
300
#B3BFE6
oklch(80.8% 0.057 271.7)
-
Step 400
400
#8C9EDA
oklch(70.8% 0.09 271.1)
-
Step 500
500
#7084D0
oklch(63% 0.117 271.5)
-
Step 600
600
#596DBD
oklch(55.7% 0.126 271.2)
-
Step 700
700 (this color)
#42539B
oklch(46.5% 0.118 271.2)
-
Step 800
800
#3C4A84
oklch(42.7% 0.098 271.5)
-
Step 900
900
#333E6A
oklch(37.6% 0.077 271.7)
-
Step 950
950
#1E253E
oklch(27.1% 0.048 271.1)
#42539B 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) | #325C9E | 0.028 |
| Deuteranopia (no green cones) | #265499 | 0.030 |
| Tritanopia (no blue cones) | #0A636F | 0.106 |
| Achromatopsia (no color) | #585858 | 0.118 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #42539B
#42539B
oklch(46.5% 0.118 271.2)
- #6D5700
#6D5700
oklch(46.6% 0.095 91.7)
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 #42539B, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight #4E518B ΔE 0.030
- Denim Blue #3B5B92 ΔE 0.030
- Dusky Blue #475F94 ΔE 0.039
- Dusk Blue #26538D ΔE 0.040
- Light Navy Blue #2E5A88 ΔE 0.046
- Dusk #4E5481 ΔE 0.046
- Blueberry #464196 ΔE 0.047
- Denim #3B638C ΔE 0.057
Use #42539B 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.