#1B3D73
Closest named color: Twilight Blue (#0A437A). oklch(36.6% 0.101 259.3), rgb(27, 61, 115).
Aa
White text reads best on this color (10.70:1).
About this color
#1B3D73 is a dark, moderately saturated blue. In OKLCH its lightness is 37%, its chroma 0.101 and its hue 259°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight Blue (#0A437A), ΔE 0.020 away. White text reads best on it, at 10.70:1.
| Hue family | Blues |
| Lightness | dark (37%) |
| Chroma | moderately saturated (0.101) |
| Temperature | cool |
| Nearest name | Twilight Blue (#0A437A) |
| Black text | 1.96:1 |
| White text | 10.70:1 |
Values
| HEX | #1B3D73 |
| RGB | rgb(27, 61, 115) |
| HSL | hsl(217, 62%, 28%) |
| OKLCH | oklch(36.6% 0.101 259.3) |
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 #1B3D73 | 10.70:1 | AAA | Lc -98.5 | Preferred for body text |
| Black text on #1B3D73 | 1.96:1 | Fails | Lc 9.4 | Not readable |
| #1B3D73 text on white | 10.70:1 | AAA | Lc 94.5 | Preferred for body text |
| #1B3D73 text on black | 1.96:1 | Fails | Lc -8.1 | 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
#F1F6FC
oklch(97.1% 0.01 252.8)
-
Step 100
100
#E1EBF9
oklch(93.7% 0.022 256.7)
-
Step 200
200
#C9DAF6
oklch(88.4% 0.043 260.4)
-
Step 300
300
#A4C2F2
oklch(80.9% 0.076 259.7)
-
Step 400
400
#72A1EC
oklch(70.7% 0.122 259.4)
-
Step 500
500
#4D88E6
oklch(63.2% 0.155 259.3)
-
Step 600
600
#2F6FD4
oklch(55.6% 0.169 259.4)
-
Step 700
700
#225CB8
oklch(49.1% 0.158 259.6)
-
Step 800
800
#1E4C95
oklch(42.8% 0.13 259.5)
-
Step 900
900 (this color)
#1B3D73
oklch(36.6% 0.101 259.3)
-
Step 950
950
#122645
oklch(27% 0.064 258.9)
#1B3D73 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) | #224275 | 0.018 |
| Deuteranopia (no green cones) | #103A72 | 0.014 |
| Tritanopia (no blue cones) | #004A52 | 0.080 |
| Achromatopsia (no color) | #3E3E3E | 0.101 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #1B3D73
#1B3D73
oklch(36.6% 0.101 259.3)
- #543900
#543900
oklch(36.6% 0.076 78.9)
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 #1B3D73, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight Blue #0A437A ΔE 0.020
- Marine Blue #01386A ΔE 0.029
- Prussian Blue #1D3557 ΔE 0.051
- Cobalt #1E488F ΔE 0.054
- Dark Grey Blue #29465B ΔE 0.058
- Light Navy #155084 ΔE 0.059
- Marine #042E60 ΔE 0.060
- Dark Blue Grey #1F3B4D ΔE 0.066
Use #1B3D73 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.