#1B5571
Closest named color: Deep Sea Blue (#015482). oklch(42.6% 0.075 233.6), rgb(27, 85, 113).
Aa
White text reads best on this color (8.12:1).
About this color
#1B5571 is a dark, moderately saturated blue. In OKLCH its lightness is 43%, its chroma 0.075 and its hue 234°. Its hue sits on the cool side of the wheel. The nearest named color is Deep Sea Blue (#015482), ΔE 0.031 away. White text reads best on it, at 8.12:1.
| Hue family | Blues |
| Lightness | dark (43%) |
| Chroma | moderately saturated (0.075) |
| Temperature | cool |
| Nearest name | Deep Sea Blue (#015482) |
| Black text | 2.58:1 |
| White text | 8.12:1 |
Values
| HEX | #1B5571 |
| RGB | rgb(27, 85, 113) |
| HSL | hsl(200, 61%, 27%) |
| OKLCH | oklch(42.6% 0.075 233.6) |
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 #1B5571 | 8.12:1 | AAA | Lc -92.5 | Preferred for body text |
| Black text on #1B5571 | 2.58:1 | Fails | Lc 16.2 | Dividers and decoration only |
| #1B5571 text on white | 8.12:1 | AAA | Lc 87.8 | Fine for body text |
| #1B5571 text on black | 2.58:1 | Fails | Lc -14.3 | 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 800.
-
Step 50
50
#F2F6F9
oklch(97.1% 0.006 239.8)
-
Step 100
100
#E2EBF1
oklch(93.5% 0.013 236.6)
-
Step 200
200
#CADCE7
oklch(88.4% 0.025 234.5)
-
Step 300
300
#A6C6D9
oklch(80.9% 0.044 234.1)
-
Step 400
400
#74A8C6
oklch(70.6% 0.07 234.4)
-
Step 500
500
#4D92B7
oklch(63% 0.089 234.1)
-
Step 600
600
#2C7CA3
oklch(55.6% 0.097 233.8)
-
Step 700
700
#1D698C
oklch(49.2% 0.09 233.3)
-
Step 800
800 (this color)
#1B5571
oklch(42.6% 0.075 233.6)
-
Step 900
900
#1E475C
oklch(37.9% 0.058 233.5)
-
Step 950
950
#122936
oklch(26.9% 0.038 235.3)
#1B5571 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) | #475472 | 0.047 |
| Deuteranopia (no green cones) | #3C4C71 | 0.040 |
| Tritanopia (no blue cones) | #005C5E | 0.046 |
| Achromatopsia (no color) | #505050 | 0.075 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #1B5571
#1B5571
oklch(42.6% 0.075 233.6)
- #6E4225
#6E4225
oklch(42.5% 0.074 52.8)
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 #1B5571, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Deep Sea Blue #015482 ΔE 0.031
- Petrol #005F6A ΔE 0.038
- Light Navy #155084 ΔE 0.039
- Deep Teal #00555A ΔE 0.043
- Light Navy Blue #2E5A88 ΔE 0.044
- YInMn Blue #415A77 ΔE 0.044
- Dusk Blue #26538D ΔE 0.050
- Dark Grey Blue #29465B ΔE 0.052
Use #1B5571 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.