Color reference

#638C42 color reference

Soft Mid-light Yellow-green

This is a soft, mid-light yellow-green under the deterministic OKLCH hue, lightness, and chroma ranges. Its closest standardized CSS named color is Olive Drab (#6B8E23), measured with straight-line OKLab distance.

Descriptive label
Soft Mid-light Yellow-green
Recommended text
Black · 5.36:1
Relative luminance
0.218022
Build a palette from #638C42 in Palette Generator Convert #638C42 in Color Converter
Formats UI preview Contrast 50–900 scale Harmonies Matches Related colors Color vision Exports

Copyable values

#638C42 in common color formats

Values are calculated from the same opaque sRGB color. Display rounding does not alter the internal calculations.

Color conversions for #638C42
Format Value Action
HEX #638C42
RGB rgb(99 140 66)
HSL hsl(93 35.92% 40.39%)
HSV hsv(93 52.86% 54.9%)
HWB hwb(93 25.88% 45.1%)
XYZ D65 color(xyz-d65 0.155064 0.218018 0.085456)
LAB lab(53.9279% -24.8369 34.3476)
LCH lch(53.9279% 42.3867 125.8709)
OKLAB oklab(59.2335% -0.076804 0.082878)
OKLCH oklch(59.2335% 0.112994 132.8216)

Real-world test

Try #638C42 on interface components

Preview the source as a primary action, subtle status, form treatment, and card surface. Persistent state controls help touch and keyboard users inspect the same normal, hover, and active colors.

Normal state uses #638C42 with black text at 5.36:1.

Action

Primary button

Use the controls above or point to and press the button to inspect its visual states.

Status

Subtle alert badge

A 12% source tint over white provides the background; readable text is selected separately.

Ready for review

Form

Border and focus ring

Source ring on white: 3.92:1 · meets the 3:1 non-text threshold where applicable.

Surface

Card component

The selected state becomes the card surface with its strongest black-or-white text pairing.

Design system Color decision ready Review states and surrounding surfaces before shipping.

Accessibility diagnostics

WCAG contrast for exact color pairs

Each result applies only to the named foreground, background, text size, and requirement. It is not a complete accessibility or component-conformance claim.

Source #638C42 Exact pair assessment Results for source text on white appear below.

On white

3.92:1

  • Fail AA normal text · 4.5:1
  • Fail AAA normal text · 7:1
  • Pass AA large text · 3:1
  • Pass UI/non-text where applicable · 3:1
Source #638C42 Exact pair assessment Results for source text on black appear below.

On black

5.36:1

  • Pass AA normal text · 4.5:1
  • Fail AAA normal text · 7:1
  • Pass AA large text · 3:1
  • Pass UI/non-text where applicable · 3:1

Use guidance

What this color may be suitable for

Not recommended

Normal-sized text

#638C42 does not reach 4.5:1 on white or Hue Codex paper, so it should not be used there for normal-sized text.

Potential fit

Controls and interface graphics

Against Hue Codex paper, the color reaches 3.75:1. That meets the 3:1 color-contrast threshold where WCAG 1.4.11 applies, but states, shape, and non-color cues still need review.

Readable pairing available

Colored surface or button fill

Black text provides the stronger black/white pairing on #638C42 at 5.36:1. This validates only that text pair, not hover, focus, disabled, or adjacent-color states.

Distinctive accent

Palette role

Its OKLCH chroma of 0.113 gives it enough visual presence for an accent or primary role when the tested foreground and neighboring colors pass.

Pair available

Color used as foreground

The stronger black/white background is black at 5.36:1. Always retest against the actual rendered background and text size.

Tested backgrounds

Foreground pairing comparison

#638C42 foreground contrast on tested backgrounds
Pair Background Contrast ratio
Black#000000 5.36:1
Hue Codex ink#10212B 4.21:1
White#FFFFFF 3.92:1
Hue Codex paper#FBFAF5 3.75:1
Soft neutral#F2EFE6 3.41:1
Check #638C42 on another background in Contrast Checker

Design-system starting point

A perceptual 50–900 reference scale

The source color is preserved at the nearest lightness step. Other swatches keep its OKLCH hue, moderate chroma toward the extremes, and reduce chroma only when needed to remain in sRGB.

50
100
200
300
400
500 #638C42 Source
600
700
800
900

This is a Hue Codex reference scale, not a claim that the values match Tailwind, Material, or another framework’s named palette.

Adjust the #638C42 scale in Tints, Shades & Tones

Color relationships

Complementary, analogous, and triadic colors

Hue rotations use OKLCH while preserving lightness and requested chroma. When a rotated result falls outside sRGB, chroma is reduced deterministically and disclosed.

Complementary

Source #638C42
Complement

Analogous

Source #638C42
Analogous −30°
Analogous +30°

Triadic

Source #638C42
Triad +120°
Triad +240°

Applied pairing

A small interface check

The source anchors the main action while the complement marks a secondary status. Contrast is selected separately for each fill.

Project color Soft Mid-light Yellow-green
Complement
Explore #638C42 in Color Harmonies

Distance matching

Closest standardized and framework colors

Matches use straight-line OKLab distance ×100. A smaller value means the coordinates are closer in this model; it is not a claim that two tokens are interchangeable in a design system.

CSS named color

Olive Drab

#6B8E23

OKLab distance ×100: 2.91

Tailwind v4 default

emerald-600

oklch(59.6% 0.145 163.225) #009966

OKLab distance ×100: 7.45 · sRGB preview #009966

Print boundary

Pantone match not estimated

Reliable print matching needs licensed reference data plus a defined ink, paper, profile, and viewing condition.

Read the print methodology

Color-vision screening

Approximate color-vision-deficiency views

These encoded-sRGB matrix previews are screening approximations. They help reveal possible color-only distinctions but do not reproduce every person’s vision or establish accessibility conformance.

Original#638C42
Approx.

Protanopia

Red-vision deficiency approximation

Original#638C42
Approx.

Deuteranopia

Green-vision deficiency approximation

Original#638C42
Approx.

Tritanopia

Blue-yellow deficiency approximation

Original#638C42
Approx.#777777

Achromatopsia

Monochromatic-vision approximation

Test #638C42 with a complete palette in the CVD Simulator

Ready to use

Copy framework-ready color tokens

Exports preserve the source, readable foreground, and generated 50–900 scale. Tailwind v4 CSS-first and Tailwind v3 JavaScript-config formats are labeled separately.

CSS custom properties

Semantic aliases and the complete 50–900 scale.

:root {
  --color-primary: #638C42;
  --color-on-primary: #000000;
  --color-primary-oklch: oklch(59.2335% 0.112994 132.8216);
  --color-primary-50: #E5FFD4;
  --color-primary-100: #CBE9B6;
  --color-primary-200: #AFD097;
  --color-primary-300: #94B879;
  --color-primary-400: #79A05B;
  --color-primary-500: #638C42;
  --color-primary-600: #4A702A;
  --color-primary-700: #365815;
  --color-primary-800: #234200;
  --color-primary-900: #152B00;
}

Tailwind v4 CSS-first theme

Current @theme syntax for bg-brand, text-brand, and scale utilities.

@import "tailwindcss";

@theme {
  --color-brand: #638C42;
  --color-brand-foreground: #000000;
  --color-brand-50: #E5FFD4;
  --color-brand-100: #CBE9B6;
  --color-brand-200: #AFD097;
  --color-brand-300: #94B879;
  --color-brand-400: #79A05B;
  --color-brand-500: #638C42;
  --color-brand-600: #4A702A;
  --color-brand-700: #365815;
  --color-brand-800: #234200;
  --color-brand-900: #152B00;
}

Tailwind v3 / legacy config

CommonJS theme.extend.colors for JavaScript-config projects.

module.exports = {
  theme: {
    extend: {
      colors: {
        brand: {
          '50': '#E5FFD4',
          '100': '#CBE9B6',
          '200': '#AFD097',
          '300': '#94B879',
          '400': '#79A05B',
          '500': '#638C42',
          '600': '#4A702A',
          '700': '#365815',
          '800': '#234200',
          '900': '#152B00',
          DEFAULT: '#638C42',
          foreground: '#000000',
        },
      },
    },
  },
};

Sass variables

Semantic source, foreground, OKLCH, and scale variables.

$color-primary: #638C42;
$color-on-primary: #000000;
$color-primary-oklch: oklch(59.2335% 0.112994 132.8216);
$color-primary-50: #E5FFD4;
$color-primary-100: #CBE9B6;
$color-primary-200: #AFD097;
$color-primary-300: #94B879;
$color-primary-400: #79A05B;
$color-primary-500: #638C42;
$color-primary-600: #4A702A;
$color-primary-700: #365815;
$color-primary-800: #234200;
$color-primary-900: #152B00;

Modern color-mix()

Static fallbacks followed by OKLab tint and shade declarations.

:root {
  --color-primary: #638C42;
  --color-primary-tint: #AFD097;
  --color-primary-tint: color-mix(in oklab, var(--color-primary) 72%, white);
  --color-primary-shade: #365815;
  --color-primary-shade: color-mix(in oklab, var(--color-primary) 82%, black);
}

JSON design data

Source formats, readable text, and the generated scale.

{
    "name": "Soft Mid-light Yellow-green",
    "hex": "#638C42",
    "rgb": "rgb(99 140 66)",
    "oklch": "oklch(59.2335% 0.112994 132.8216)",
    "recommendedText": "#000000",
    "scale": {
        "50": "#E5FFD4",
        "100": "#CBE9B6",
        "200": "#AFD097",
        "300": "#94B879",
        "400": "#79A05B",
        "500": "#638C42",
        "600": "#4A702A",
        "700": "#365815",
        "800": "#234200",
        "900": "#152B00"
    }
}

Continue the decision

Use #638C42 in a complete workflow

Reference values are a starting point. Test the color in its real role, background, states, typography, and surrounding palette before shipping.

Adjust #638C42 in Color PickerStart with this exact color and white as the working background for role and accessibility decisions. Build a palette from #638C42 in Palette GeneratorUse this exact HEX as the seed for a deterministic, role-based palette. Check #638C42 on white in Contrast CheckerStart with this color as the foreground and white as the background, then test the real pair.