#17398E
Closest named color: Cobalt (#1E488F). oklch(37.8% 0.147 264), rgb(23, 57, 142).
Aa
White text reads best on this color (10.43:1).
About this color
#17398E is a dark, vivid blue. In OKLCH its lightness is 38%, its chroma 0.147 and its hue 264°. Its hue sits on the cool side of the wheel. The nearest named color is Cobalt (#1E488F), ΔE 0.042 away. White text reads best on it, at 10.43:1.
| Hue family | Blues |
| Lightness | dark (38%) |
| Chroma | vivid (0.147) |
| Temperature | cool |
| Nearest name | Cobalt (#1E488F) |
| Black text | 2.01:1 |
| White text | 10.43:1 |
Values
| HEX | #17398E |
| RGB | rgb(23, 57, 142) |
| HSL | hsl(223, 72%, 32%) |
| OKLCH | oklch(37.8% 0.147 264) |
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 #17398E | 10.43:1 | AAA | Lc -97.7 | Preferred for body text |
| Black text on #17398E | 2.01:1 | Fails | Lc 10.3 | Not readable |
| #17398E text on white | 10.43:1 | AAA | Lc 93.6 | Preferred for body text |
| #17398E text on black | 2.01:1 | Fails | Lc -8.9 | 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
#F1F6FF
oklch(97.2% 0.013 262.4)
-
Step 100
100
#E0EAFF
oklch(93.6% 0.03 265.3)
-
Step 200
200
#C7DAFF
oklch(88.6% 0.055 263.7)
-
Step 300
300
#A1C0FF
oklch(80.8% 0.096 264.1)
-
Step 400
400
#6F9DFF
oklch(70.7% 0.152 263.9)
-
Step 500
500
#4A80FF
oklch(63.1% 0.198 264.2)
-
Step 600
600
#235FFF
oklch(55.6% 0.245 264.1)
-
Step 700
700
#184DDE
oklch(49.1% 0.227 264)
-
Step 800
800
#1540B4
oklch(42.6% 0.189 264.1)
-
Step 900
900 (this color)
#17398E
oklch(37.8% 0.147 264)
-
Step 950
950
#0E2253
oklch(26.9% 0.093 264.3)
#17398E 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) | #004591 | 0.031 |
| Deuteranopia (no green cones) | #003A8C | 0.013 |
| Tritanopia (no blue cones) | #004F5D | 0.115 |
| Achromatopsia (no color) | #404040 | 0.147 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #17398E
#17398E
oklch(37.8% 0.147 264)
- #553D00
#553D00
oklch(37.7% 0.077 83.5)
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 #17398E, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Cobalt #1E488F ΔE 0.042
- Twilight Blue #0A437A ΔE 0.046
- Sapphire #2138AB ΔE 0.049
- Marine Blue #01386A ΔE 0.064
- Dark Slate Blue #483D8B ΔE 0.067
- Blueberry #464196 ΔE 0.068
- Light Navy #155084 ΔE 0.069
- Royal #0C1793 ΔE 0.072
Use #17398E 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.