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Understanding Color Spaces: HEX, RGB, HSL, and Beyond

A comprehensive guide to color spaces used in web design and digital art. Learn when to use HEX, RGB, HSL, CMYK, and the new OKLCH format.

March 26, 2025LangColor

Every color you see on screen is just a set of numbers. But different systems use different numbers to describe the same color. Understanding these systems — called color spaces — is essential for any designer or developer working with color.

HEX — The Web Standard

HEX codes like #FF6B35 are the most familiar format for web colors. They pack Red, Green, and Blue values into a 6-character string.

.button {
  background-color: #FF6B35;
  color: #ffffff;
}

RGB — Red, Green, Blue

RGB is the foundation. Every screen pixel mixes red, green, and blue light. Values range from 0–255 per channel.

HSL — Hue, Saturation, Lightness

HSL maps color to human perception. Instead of mixing light channels, you describe:

This makes HSL the best choice for programmatic color manipulation:

/* Easy to create hover states */
.button { background: hsl(20, 100%, 60%); }
.button:hover { background: hsl(20, 100%, 55%); } /* just darken 5% */

OKLCH — The Future

OKLCH is a perceptually uniform color space. "Perceptually uniform" means equal numeric changes produce equal visual changes — unlike HSL where hsl(120, 100%, 50%) and hsl(60, 100%, 50%) look very different in brightness.

.accent { color: oklch(70% 0.2 30); }

OKLCH is already supported in all modern browsers and is the recommended color space in CSS Color Level 4.

When to Use What

| Color Space | Best For | |---|---| | HEX | Quick sharing, design specs | | RGB | Channel manipulation, Canvas API | | HSL | UI themes, dynamic color generation | | CMYK | Print design | | OKLCH | Perceptually uniform palettes, accessibility |

Try It with LangColor

You can convert between all these color spaces instantly with the Color Converter tool. Or use the AI Palette Generator to create harmonious palettes in any format.


Want to dive deeper? Check out our Contrast Checker to ensure your color choices meet WCAG accessibility standards.

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