#1B375E
Closest named color: Prussian Blue (#1D3557). oklch(33.6% 0.077 257.1), rgb(27, 55, 94).
Aa
White text reads best on this color (11.96:1).
About this color
#1B375E is a dark, moderately saturated blue. In OKLCH its lightness is 34%, its chroma 0.077 and its hue 257°. Its hue sits on the cool side of the wheel. The nearest named color is Prussian Blue (#1D3557), ΔE 0.013 away. White text reads best on it, at 11.96:1.
| Hue family | Blues |
| Lightness | dark (34%) |
| Chroma | moderately saturated (0.077) |
| Temperature | cool |
| Nearest name | Prussian Blue (#1D3557) |
| Black text | 1.75:1 |
| White text | 11.96:1 |
Values
| HEX | #1B375E |
| RGB | rgb(27, 55, 94) |
| HSL | hsl(215, 55%, 24%) |
| OKLCH | oklch(33.6% 0.077 257.1) |
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 #1B375E | 11.96:1 | AAA | Lc -100.8 | Preferred for body text |
| Black text on #1B375E | 1.75:1 | Fails | Lc 0.0 | Not readable |
| #1B375E text on white | 11.96:1 | AAA | Lc 97.2 | Preferred for body text |
| #1B375E text on black | 1.75:1 | 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
#F2F6FB
oklch(97.2% 0.008 253.9)
-
Step 100
100
#E3EBF5
oklch(93.7% 0.016 253.9)
-
Step 200
200
#CCDAEF
oklch(88.4% 0.033 258.4)
-
Step 300
300
#A9C3E6
oklch(81% 0.057 255.9)
-
Step 400
400
#7BA3DA
oklch(70.8% 0.092 256.5)
-
Step 500
500
#598BD0
oklch(63.2% 0.118 256.7)
-
Step 600
600
#3E73BD
oklch(55.5% 0.129 257.1)
-
Step 700
700
#3060A3
oklch(49% 0.12 257.2)
-
Step 800
800
#294F84
oklch(42.7% 0.099 257.1)
-
Step 900
900 (this color)
#1B375E
oklch(33.6% 0.077 257.1)
-
Step 950
950
#16273E
oklch(27% 0.049 256.3)
#1B375E 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) | #263A60 | 0.017 |
| Deuteranopia (no green cones) | #1C345D | 0.009 |
| Tritanopia (no blue cones) | #004046 | 0.061 |
| Achromatopsia (no color) | #373737 | 0.077 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #1B375E
#1B375E
oklch(33.6% 0.077 257.1)
- #4B3100
#4B3100
oklch(33.6% 0.07 76.6)
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 #1B375E, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Prussian Blue #1D3557 ΔE 0.013
- Marine Blue #01386A ΔE 0.026
- Dark Blue Grey #1F3B4D ΔE 0.036
- Marine #042E60 ΔE 0.037
- Midnight Green #073B4C ΔE 0.041
- Gunmetal #293241 ΔE 0.052
- Space Cadet #2B2D42 ΔE 0.054
- Dark Grey Blue #29465B ΔE 0.055
Use #1B375E 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.