#1B3759
Closest named color: Prussian Blue (#1D3557). oklch(33.3% 0.069 254.4), rgb(27, 55, 89).
Aa
White text reads best on this color (12.08:1).
About this color
#1B3759 is a dark, muted blue. In OKLCH its lightness is 33%, its chroma 0.069 and its hue 254°. Its hue sits on the cool side of the wheel. The nearest named color is Prussian Blue (#1D3557), ΔE 0.007 away. White text reads best on it, at 12.08:1.
| Hue family | Blues |
| Lightness | dark (33%) |
| Chroma | muted (0.069) |
| Temperature | cool |
| Nearest name | Prussian Blue (#1D3557) |
| Black text | 1.73:1 |
| White text | 12.08:1 |
Values
| HEX | #1B3759 |
| RGB | rgb(27, 55, 89) |
| HSL | hsl(213, 53%, 23%) |
| OKLCH | oklch(33.3% 0.069 254.4) |
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 #1B3759 | 12.08:1 | AAA | Lc -101.0 | Preferred for body text |
| Black text on #1B3759 | 1.73:1 | Fails | Lc 0.0 | Not readable |
| #1B3759 text on white | 12.08:1 | AAA | Lc 97.5 | Preferred for body text |
| #1B3759 text on black | 1.73:1 | 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
#F2F6FA
oklch(97.1% 0.007 247.9)
-
Step 100
100
#E3EBF4
oklch(93.7% 0.015 251.2)
-
Step 200
200
#CDDBEC
oklch(88.6% 0.028 253.2)
-
Step 300
300
#AAC3E2
oklch(80.9% 0.052 253.9)
-
Step 400
400
#7DA3D4
oklch(70.6% 0.083 255.1)
-
Step 500
500
#5B8CC9
oklch(63.1% 0.107 254.6)
-
Step 600
600
#4075B5
oklch(55.6% 0.115 254.3)
-
Step 700
700
#32629C
oklch(49.1% 0.107 254.5)
-
Step 800
800
#2A507F
oklch(42.7% 0.09 254.8)
-
Step 900
900 (this color)
#1B3759
oklch(33.3% 0.069 254.4)
-
Step 950
950
#17273C
oklch(27% 0.045 255.6)
#1B3759 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) | #28395A | 0.018 |
| Deuteranopia (no green cones) | #203358 | 0.013 |
| Tritanopia (no blue cones) | #003F43 | 0.057 |
| Achromatopsia (no color) | #363636 | 0.069 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #1B3759
#1B3759
oklch(33.3% 0.069 254.4)
- #4B3001
#4B3001
oklch(33.4% 0.07 74.6)
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 #1B3759, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Prussian Blue #1D3557 ΔE 0.007
- Dark Blue Grey #1F3B4D ΔE 0.028
- Marine Blue #01386A ΔE 0.033
- Midnight Green #073B4C ΔE 0.034
- Marine #042E60 ΔE 0.040
- Gunmetal #293241 ΔE 0.044
- Space Cadet #2B2D42 ΔE 0.048
- Dark Grey Blue #29465B ΔE 0.053
Use #1B3759 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.