Conversions, palettes, contrast & design ideas for this color.
Color profile
#639941 is a cool color from the Green family, closest in name to “Bitter Leaf”. In RGB it is rgb(99, 153, 65); in HSL, hsl(97, 40%, 43%).
The color Bitter Leaf, with hexadecimal code #639941, resides within the green color family, the hue most connected to nature, growth, and renewal. Green soothes the eye more than any other color, making it ideal for wellness, sustainability, and financial brands. Additionally, it evokes emotions such as Nature, Healing, Balance, Stability and Calmness. Green is often linked to nature and growth universally, and in some cultures, it symbolizes fertility, renewal, and even immortality. In Islam, green holds significant religious meaning. With a moderate saturation of 40%, it has a softened, muted quality that lends sophistication and works well for backgrounds and secondary elements. With a mid-range lightness of 43%, it offers excellent versatility—readable as text on light backgrounds and visible as an element on dark ones. This color is ideal for designs that aim to express Nature, Healing, Balance, Stability, or Calmness. It can be effectively used in web design, branding, and marketing materials to attract attention and convey specific messages.
Key facts
The story of this color
Bitter Leaf (#639941) belongs to the Green color family.
With moderate saturation and balanced lightness, this muted tone feels sophisticated and understated. Muted hues like this excel in editorial design, professional portfolios, and interior spaces that seek calm refinement.
Green pigments were notoriously difficult to produce until modern chemistry. Ancient Egyptians used malachite, while Scheele's Green (1775) and Paris Green contained lethal arsenic—reportedly sickening Napoleon in his green-wallpapered exile room. In Islam, green symbolizes paradise and is associated with the Prophet Muhammad. Celtic traditions link green to the fae realm and the untamed forces of nature.
Green is the universal signifier of nature, sustainability, and health. It dominates eco-brands, organic food labels, and wellness apps. Medium greens work as primary brand colors, while darker greens (forest, hunter) lend gravitas to financial and legal institutions. Pair green with earth tones for authenticity or with white for clinical freshness.
Sitting on the cool side of the spectrum (hue 97°), it promotes a feeling of calm distance and intellectual clarity, which is why cool hues dominate corporate identities, healthcare design, and productivity tools. At 40% saturation, the color has a muted, sophisticated quality that pairs well with bolder accents. It works as a background, a border, or a secondary element in layered compositions.
Green is the easiest color for the human eye to process, which is why it feels restful and balancing. It lowers stress, encourages concentration, and symbolizes renewal. In UX, green universally signals success, completion, and safe-to-proceed actions.
With a mid-range lightness of 43%, this tone is highly versatile: dark enough to serve as body text on white, yet light enough to stand out on charcoal or navy backgrounds.
Create depth with a dark-to-light green gradient background for nature-themed landing pages. Use forest green with gold serif typography for a classic, trustworthy brand identity. In data visualization, green represents positive trends, growth, and on-target metrics.
Every format
Every way to write Bitter Leaf — one-tap copy on every format; tap on any card to learn what it is and when to use it.
#639941
Hexadecimal is the web’s universal color notation — two digits each for red, green and blue. Drop it straight into HTML, CSS or any design tool.
rgb(99, 153, 65)
RGB is the additive Red-Green-Blue model every screen uses to emit light. The default choice for websites, apps and on-screen UI.
hsl(97, 40%, 43%)
HSL breaks a color into Hue, Saturation and Lightness — the most intuitive way to lighten, darken or mute a color in CSS.
hsv(97, 58%, 60%)
HSV (also called HSB) maps Hue, Saturation and Value/Brightness. It is the model behind the color pickers in Photoshop, Figma and most design apps.
hwb(97 25% 40%)
HWB blends a pure hue with Whiteness and Blackness — a painter-friendly model added in CSS Color 4 for quick tints and shades.
cmyk(35%, 0%, 58%, 40%)
CMYK is the subtractive Cyan-Magenta-Yellow-Black ink model. Use these values when preparing artwork for a printer or commercial press.
oklch(62.52% 0.133 134.94)
OKLCH is a modern, perceptually-uniform space (Lightness, Chroma, Hue). It powers smooth gradients and accessible palettes in today’s CSS.
oklab(62.52% -0.094 0.094)
OKLab is the Cartesian form of OKLCH — ideal for blending and interpolating colors without the muddy midpoints older spaces produce.
L: 57.86, a: -33.97, b: 40.03
CIELAB is a device-independent, perceptually-uniform space. It is the standard for measuring color difference (ΔE) and matching across devices.
L: 57.86, C: 52.50, H: 130.32
LCH is CIELAB in cylindrical form — Lightness, Chroma and Hue — letting you adjust vividness and hue while staying perceptually even.
X: 17.49, Y: 25.82, Z: 9.06
CIE XYZ is the 1931 master space that underpins every other model here — the scientific bridge used to convert between color systems.
6527297
The 24-bit integer value of the color — handy for databases, APIs, game engines and low-level graphics code.
Channel breakdown
How much red, green and blue light mixes into Bitter Leaf.
Percentages show each channel's share of the total light (R + G + B) in Bitter Leaf.
Ink coverage
Ink needed to reproduce Bitter Leaf in four-color print. Heaviest ink: Yellow.
Print tip: treat these values as a starting point — final output depends on printer profile, paper stock and calibration.
Accessibility · WCAG
How bright Bitter Leaf is, and how far black and white text clear each WCAG bar.
Contrast ratio · 1:1 → 21:1 (log scale)
Developer shortcuts
Copy-and-paste CSS for Bitter Leaf — per-line copy, or grab the whole block.
background-color: #639941;
color: #639941;
border: 2px solid #639941;
background-color: rgb(99, 153, 65);
background-color: hsl(97, 40%, 43%);
--color: #639941;
Shades · light to dark
Lighter and darker steps of Bitter Leaf — the color's full brightness range in one strip.
The dot marks the original color. Hover any shade to copy its hex or open its color page.
Harmony · 180° apart
Two colors opposite on the wheel — maximum contrast for attention-grabbing accents.
The dot marks the original color. Hover any shade to copy its hex or open its color page.
Harmony · adjacent hues
Neighboring hues on the wheel — harmonious, calm combinations that feel unified.
The dot marks the original color. Hover any shade to copy its hex or open its color page.
Harmony · 120° apart
Three colors evenly spaced on the wheel — vibrant and energetic, yet balanced.
The dot marks the original color. Hover any shade to copy its hex or open its color page.
Harmony · 90° apart
Four colors evenly spaced on the wheel (tetradic) — rich schemes with multiple accents.
The dot marks the original color. Hover any shade to copy its hex or open its color page.
Accessibility
How Bitter Leaf reads across five kinds of color vision — a ✓ Friendly verdict means the color difference stays distinguishable for that vision type.
The dot marks the original color. Hover any shade to copy its hex.
Harmony overview
The lead color from each harmony scheme, side by side — a shortcut to the full palettes above.
Perceptually nearby
A step away in brightness, richness or shade — each still feels like the same color.
From the color-name library
The closest named colors to #639941 — same mood, each with its own character.
Looking for more Green shades? Browse Green colors →
Inspiration
Curated Unsplash photos that carry the mood of Bitter Leaf — hover any tile to download it or view the original.
Good to know
Harmony