RAL Classic color

RAL 5004 Black blue #18171C

RAL 5004 Black blue is shown here as #18171C, a widely published sRGB approximation of the printed swatch. It is a near-black in the neutral family. In OKLCH it sits at lightness 0.208 with chroma 0.010, too low for hue to matter. The nearest CSS named color is black (#000000), ΔE2000 6.2 away.

Relative luminance
0.0089
OKLCH L · C · h
0.208 · 0.010 · 294.7
Best text
White 17.82:1
Hue family
Neutral
Inspect this color Check contrast

#18171C color codes

HEX
#18171C
RGB
rgb(24, 23, 28)
HSL
hsl(252, 10%, 10%)
OKLCH
oklch(0.208 0.010 294.7)
OKLab
oklab(0.208 0.004 -0.009)
CIELAB (D65)
L* 8.05, a* 1.84, b* -3.33
XYZ (D65)
X 0.89, Y 0.89, Z 1.22
CMYK (naive)
cmyk(14%, 18%, 0%, 89%)

CIELAB and XYZ use the D65 white point; CSS lab() uses D50, so paste the OKLCH or HEX value into stylesheets. CMYK here is a plain formula with no press profile.

RAL and RAL Classic are trademarks of RAL gGmbH, which this site is not affiliated with. The sRGB value is an approximation of the printed swatch; check a physical RAL color card before you specify a paint.

Legibility

Contrast: is #18171C accessible?

White text on it reaches 17.82:1, passing AAA. Black text fails at 1.17:1.

WCAG 2 gives the same ratio whichever color is the text; APCA does not, so its Lc changes sign and size with polarity.

Open the Contrast System

  • Black text on it

    1.17:1

    • AA fails
    • AA large fails
    • AAA fails
    • APCA Lc 0

    Text is here, unreadable at 1.17:1

  • White text on it

    17.82:1

    • AA passes
    • AA large passes
    • AAA passes
    • APCA Lc −106

  • As text on black

    1.17:1

    • AA fails
    • AA large fails
    • AAA fails
    • APCA Lc 0

    Text is here, unreadable at 1.17:1

  • As text on white

    17.82:1

    • AA passes
    • AA large passes
    • AAA passes
    • APCA Lc +104

Nearest versions that pass 4.5:1

  • For text on white

    #18171C 17.82:1

    It already reaches 17.82:1 on white, so no change is needed.

  • For text on black

    #75747B 4.54:1

    Lightening its OKLCH lightness from 0.21 to 0.56 reaches 4.54:1 on black, keeping the hue.

    Compare both in the Contrast System

Checking another pair? Use the Contrast Checker.

Studio

Adjust #18171C live

Move lightness, chroma and hue in OKLCH, or drag on the map. The map is every lightness and chroma at the current hue: sRGB inside the solid area, Display P3 out to the dashed line.

The studio needs JavaScript.

Scale

Shades and tints of #18171C

Eleven OKLCH lightness steps at this hue, each with its contrast against white and black. #18171C sits at step 950.

  1. 50#F5F4FA
    White
    1.09
    Black
    19.20
  2. 100#EBEAF0
    White
    1.19
    Black
    17.55
  3. 200#D8D6DD
    White
    1.44
    Black
    14.58
  4. 300#BEBDC3
    White
    1.86
    Black
    11.25
  5. 400#A2A0A7
    White
    2.58
    Black
    8.12
  6. 500#86858C
    White
    3.65
    Black
    5.74
  7. 600#6F6E74
    White
    5.04
    Black
    4.15
  8. 700#58575D
    White
    7.15
    Black
    2.93
  9. 800#403F44
    White
    10.43
    Black
    2.01
  10. 900#29282D
    White
    14.62
    Black
    1.43
  11. 950This color#18171C
    White
    17.82
    Black
    1.17

Under each step, white and black text on it; a bold figure passes 4.5:1.

Gamut

How vivid #18171C can get

A gray has no hue, so no gamut holds a more vivid version of #18171C: more chroma would make it another color.

0.00.20.40.60.80.20.40.60.8 460480500520540560580600620
  • sRGB
  • Display P3
  • Rec. 2020
  • Dominant wavelength
OKLCH chroma
0.010
sRGB edge
No hue
Display P3 edge
No hue
Rec. 2020 edge
No hue
Dominant wavelength
446 nm
Excitation purity
10%
Chromaticity
x 0.2969, y 0.2963

Mixing

Mixing #18171C

Each row is the same mix worked out in a different space, with the halfway color at its end. sRGB, which older CSS gradients use, can sag gray or dark in the middle; OKLab keeps the lightness steps even; OKLCH holds chroma and hue as it goes.

White #FFFFFF

  • sRGB50%#8C8B8E
  • OKLab50%#818184
  • OKLCH50%#818184

Black #000000

  • sRGB50%#0C0C0E
  • OKLab50%#040405
  • OKLCH50%#040405
In CSS
/* A gradient and a mix, worked out in OKLCH */
background: linear-gradient(in oklch, #18171c, white);
color: color-mix(in oklch, #18171c 50%, white);

In use

#18171C in an interface

A button, a link, a heading, a focused field, an icon and a chart line in this color, on a light page and a dark one. Each check is a WCAG 2 contrast minimum: 1.4.3 for text, 1.4.11 for the rest.

Light page

  • Button labelText, 4.5:117.82:1 Passes
  • Link and body-size textText, 4.5:117.82:1 Passes
  • Large headingLarge text, 3:117.82:1 Passes
  • Icons, borders and focus ringsNon-text, 3:117.82:1 Passes

Dark page

  • Button labelText, 4.5:117.82:1 Passes
  • Link and body-size textText, 4.5:11.05:1 Fails
  • Large headingLarge text, 3:11.05:1 Fails
  • Icons, borders and focus ringsNon-text, 3:11.05:1 Fails

For text on this page, the nearest shade that passes is #7D7C82 4.52:1

Color vision

How #18171C looks with color blindness

As a neutral it barely changes under any simulation, ΔE2000 3.9 at most.

Simulated with Machado et al. (2009) at full severity, in linear light.

Simulate a whole page What each type sees

  • Protanopia

    No working red (long-wavelength) cones

    #16181C ΔE2000 2.4

    Close match

    Reads as near-black

  • Deuteranopia

    No working green (medium-wavelength) cones

    #16181C ΔE2000 2.4

    Close match

    Reads as near-black

  • Tritanopia

    No working blue (short-wavelength) cones

    #171819 ΔE2000 3.6

    Close match

    Reads as near-black

  • Achromatopsia

    No cone color vision; lightness only

    #181818 ΔE2000 3.9

    Close match

    Reads as near-black

Pairing check

A near-neutral has no complementary hue to pair with, so tell it apart from neighboring grays by lightness contrast alone.

Harmony

Color harmonies for #18171C

A neutral has no hue to rotate, so every harmony collapses back to the same gray. Pair it with an accent color instead.

Or pair it by lightness: steps of its own scale as text on it, and what each can carry.

Build a lightness scale in Harmony Studio

  • Step 50 #F5F4FA · 16.29:1

    Body text, AAA

  • Step 300 #BEBDC3 · 9.55:1

    Body text, AAA

  • Step 700 #58575D · 2.49:1

    Decoration only, under 3:1

Code

Design tokens

Ready-to-paste tokens in six formats. Rename them to fit your system.

CSS custom property

:root {
  --color-ral-5004: #18171c;
}

Tailwind config

// tailwind.config.js
module.exports = {
  theme: {
    extend: {
      colors: {
        'ral-5004': '#18171c',
      },
    },
  },
};

Tailwind v4 theme

/* app.css — Tailwind CSS v4 */
@import "tailwindcss";

@theme {
  --color-ral-5004: oklch(0.208 0.010 294.7);
}

Design token (W3C DTCG)

{
  "color": {
    "ral-5004": {
      "$type": "color",
      "$value": {
        "colorSpace": "srgb",
        "components": [0.0941, 0.0902, 0.1098],
        "hex": "#18171c"
      },
      "$description": "RAL 5004 Black blue (approximate sRGB)"
    }
  }
}

SwiftUI color

import SwiftUI

enum Palette {
    static let ral5004 = Color(.sRGB, red: 0.094, green: 0.090, blue: 0.110, opacity: 1)
}

Jetpack Compose color

import androidx.compose.ui.graphics.Color

object Palette {
    val Ral5004 = Color(0xFF18171C)
}

Matches

The nearest match in each system

The closest CSS name, Tailwind shade, RAL Classic paint and Crayola crayon by ΔE2000; under 2 is hard to tell apart side by side. RAL and Crayola values approximate physical colors.

Neighbors

The eight nearest colors on this site by ΔE2000, closest first. Under 2 is hard to tell apart side by side.

Tools

Open #18171C in the tools

Each opens over this page. More colors live in the Color Library, and every color page is listed on the hub.