Conversions, palettes, contrast & design ideas for this color.
Color profile
#C6E421 is a warm color from the Yellow family, closest in name to “Sour Green”. In RGB it is rgb(198, 228, 33); in HSL, hsl(69, 78%, 51%).
The color Sour Green, with hexadecimal code #c6e421, resides in the yellow color family, the most visible hue in the spectrum. Yellow radiates optimism, intellect, and cheerful energy—qualities that made it the imperial color of ancient China. Additionally, it evokes emotions such as Freshness, Harmony, Growth, Youthfulness and Renewal. Yellow represents wealth, glory, and wisdom in various cultures, including being the color of royalty in ancient China. It is also associated with happiness and optimism in many Western cultures. At 78% saturation, this color is clearly chromatic yet balanced—colorful enough to be distinctive without overwhelming adjacent content. With a mid-range lightness of 51%, 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 Freshness, Harmony, Growth, Youthfulness, or Renewal. 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
Sour Green (#C6E421) belongs to the Yellow color family.
This vivid mid-tone strikes the ideal balance between intensity and readability, making it a strong candidate for primary brand colors, interactive UI elements, and logo design where immediate recognition is essential.
Yellow ochre was one of the first pigments used in cave art, and later Egyptians produced orpiment—a toxic arsenic-based yellow—for tomb paintings. In imperial China, only the emperor could wear bright yellow, making it the most restricted color in the nation. Van Gogh famously obsessed over chrome yellow, using it lavishly in his Sunflowers series and Arles landscapes.
Yellow is the most visible color in daylight, which is why it dominates warning signs, taxi cabs, and highlighter pens. Use it for attention-grabbing headlines or promotional banners, but ensure sufficient contrast with text—dark gray or black on yellow maintains readability. Avoid large yellow backgrounds on screens, as they can cause eye fatigue.
Positioned on the warm side of the color wheel (hue 69°), it naturally draws the eye and creates a sense of closeness—making it effective for calls to action, food photography, and hospitality branding. With 78% saturation, it occupies a comfortable middle ground: colorful enough to be distinctive, yet restrained enough for extended reading or large surface areas.
Yellow radiates optimism, intellect, and energy. It stimulates mental activity and generates a sense of cheerfulness, which makes it popular in children's products and educational materials. However, overly bright yellows can provoke anxiety, so context and tone matter.
With a mid-range lightness of 51%, 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.
Pair canary yellow with charcoal for a modern, high-contrast editorial style. Use soft butter yellow as a background for recipe blogs or lifestyle content to evoke warmth. In branding, a yellow logomark on a white background signals innovation and forward-thinking (think Snapchat or National Geographic).
Every format
Every way to write Sour Green — one-tap copy on every format; tap on any card to learn what it is and when to use it.
#C6E421
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(198, 228, 33)
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(69, 78%, 51%)
HSL breaks a color into Hue, Saturation and Lightness — the most intuitive way to lighten, darken or mute a color in CSS.
hsv(69, 86%, 89%)
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(69 13% 11%)
HWB blends a pure hue with Whiteness and Blackness — a painter-friendly model added in CSS Color 4 for quick tints and shades.
cmyk(13%, 0%, 86%, 11%)
CMYK is the subtractive Cyan-Magenta-Yellow-Black ink model. Use these values when preparing artwork for a printer or commercial press.
oklch(86.69% 0.197 119.07)
OKLCH is a modern, perceptually-uniform space (Lightness, Chroma, Hue). It powers smooth gradients and accessible palettes in today’s CSS.
oklab(86.69% -0.096 0.173)
OKLab is the Cartesian form of OKLCH — ideal for blending and interpolating colors without the muddy midpoints older spaces produce.
L: 85.81, a: -31.71, b: 80.22
CIELAB is a device-independent, perceptually-uniform space. It is the standard for measuring color difference (ΔE) and matching across devices.
L: 85.81, C: 86.26, H: 111.57
LCH is CIELAB in cylindrical form — Lightness, Chroma and Hue — letting you adjust vividness and hue while staying perceptually even.
X: 51.31, Y: 67.60, Z: 11.78
CIE XYZ is the 1931 master space that underpins every other model here — the scientific bridge used to convert between color systems.
13034529
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 Sour Green.
Percentages show each channel's share of the total light (R + G + B) in Sour Green.
Ink coverage
Ink needed to reproduce Sour Green 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 Sour Green 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 Sour Green — per-line copy, or grab the whole block.
background-color: #C6E421;
color: #C6E421;
border: 2px solid #C6E421;
background-color: rgb(198, 228, 33);
background-color: hsl(69, 78%, 51%);
--color: #C6E421;
Shades · light to dark
Lighter and darker steps of Sour Green — 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 Sour Green 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 #C6E421 — same mood, each with its own character.
Looking for more Yellow shades? Browse Yellow colors →
Inspiration
Curated Unsplash photos that carry the mood of Sour Green — hover any tile to download it or view the original.
Good to know
Harmony