#1B3E73
Closest named color: Twilight Blue (#0A437A). oklch(36.9% 0.1 258.6), rgb(27, 62, 115).
Aa
White text reads best on this color (10.58:1).
About this color
#1B3E73 is a dark, moderately saturated blue. In OKLCH its lightness is 37%, its chroma 0.100 and its hue 259°. Its hue sits on the cool side of the wheel. The nearest named color is Twilight Blue (#0A437A), ΔE 0.018 away. White text reads best on it, at 10.58:1.
| Hue family | Blues |
| Lightness | dark (37%) |
| Chroma | moderately saturated (0.100) |
| Temperature | cool |
| Nearest name | Twilight Blue (#0A437A) |
| Black text | 1.98:1 |
| White text | 10.58:1 |
Values
| HEX | #1B3E73 |
| RGB | rgb(27, 62, 115) |
| HSL | hsl(216, 62%, 28%) |
| OKLCH | oklch(36.9% 0.1 258.6) |
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 #1B3E73 | 10.58:1 | AAA | Lc -98.2 | Preferred for body text |
| Black text on #1B3E73 | 1.98:1 | Fails | Lc 9.7 | Not readable |
| #1B3E73 text on white | 10.58:1 | AAA | Lc 94.3 | Preferred for body text |
| #1B3E73 text on black | 1.98:1 | Fails | Lc -8.3 | 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
#C9DAF5
oklch(88.4% 0.042 259.6)
-
Step 300
300
#A3C2F1
oklch(80.8% 0.075 258.6)
-
Step 400
400
#72A1EB
oklch(70.6% 0.12 259.2)
-
Step 500
500
#4C88E4
oklch(63.1% 0.153 258.7)
-
Step 600
600
#2E70D2
oklch(55.6% 0.165 258.6)
-
Step 700
700
#205DB6
oklch(49.1% 0.154 258.5)
-
Step 800
800
#1D4C94
oklch(42.7% 0.129 259)
-
Step 900
900 (this color)
#1B3E73
oklch(36.9% 0.1 258.6)
-
Step 950
950
#122645
oklch(27% 0.064 258.9)
#1B3E73 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) | #244375 | 0.019 |
| Deuteranopia (no green cones) | #133B72 | 0.012 |
| Tritanopia (no blue cones) | #004A53 | 0.077 |
| Achromatopsia (no color) | #3F3F3F | 0.100 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #1B3E73
#1B3E73
oklch(36.9% 0.1 258.6)
- #553900
#553900
oklch(36.8% 0.077 77.9)
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 #1B3E73, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Twilight Blue #0A437A ΔE 0.018
- Marine Blue #01386A ΔE 0.031
- Prussian Blue #1D3557 ΔE 0.052
- Cobalt #1E488F ΔE 0.053
- Dark Grey Blue #29465B ΔE 0.055
- Light Navy #155084 ΔE 0.056
- Marine #042E60 ΔE 0.062
- Dark Blue Grey #1F3B4D ΔE 0.066
Use #1B3E73 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.