Guides
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Latest guide
Why Print Colors Never Match Your Screen: CMYK Explained
Screens emit light; paper reflects it. That single physical difference is why CMYK exists, why it needs a fourth ink, and why your brand color looks different on a business card than in a browser.
Jul 17, 2026 · 3 min read · Color Theory
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HSL vs HSV: Two Ways to Slice the Same Colors
HSL and HSV both reorganize RGB around hue, but their third axes mean different things — and picking the wrong one for the job is a common source of confusion. Here's the actual difference.
Jul 17, 2026 · 3 min read · Color Theory
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The RGB Color Model: How Screens Actually Make Color
Every pixel on your screen is three tiny lights. Understanding how red, green, and blue add up to every color you see explains why RGB values work the way they do — and why 255 is the magic number.
Jul 17, 2026 · 12 min read · Color Theory
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What Is Delta E? Measuring How Different Two Colors Really Are
Two colors can have very different RGB or HEX values yet look almost identical — or the reverse. Delta E is the standard way to measure perceptual color difference instead of relying on raw numeric distance.
Jul 17, 2026 · 2 min read · Color Theory
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What Is OKLCH, and Why Are Browsers Switching to It?
CSS now supports oklch() natively, and Tailwind CSS v4 uses it for its entire default palette. Here's what makes OKLCH different from HSL, and why it produces better results for things like generating shades or blending colors.
Jul 17, 2026 · 2 min read · Color Theory
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Color Harmony 101: Complementary, Analogous, Triadic, and More
Every classic color scheme — complementary, analogous, triadic, tetradic — comes from the same idea: picking hues at specific angles around the color wheel. Here's what each one actually does.
Jul 17, 2026 · 2 min read · Design
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WCAG Contrast Ratios Explained: What AA and AAA Actually Require
WCAG contrast requirements aren't arbitrary — they're built from a specific luminance formula. Here's how the ratio is calculated, what AA and AAA actually require, and why 4.5:1 became the standard.
Jul 17, 2026 · 2 min read · Accessibility
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What Is HEX? A Practical Guide to Hexadecimal Color Codes
HEX codes are the six-digit shorthand browsers and design tools use to represent color. Here's how they're built, and when to reach for HEX over RGB or HSL.
Jul 17, 2026 · 2 min read · Color Theory
Learning path: color formats, in order
These guides build on each other — start at HEX and by the end you'll know why perceptual color spaces exist, what ΔE measures, and how to prove your colors are readable. About 26 minutes total.
- 1 What Is HEX? A Practical Guide to Hexadecimal Color Codes 2 min read
- 2 The RGB Color Model: How Screens Actually Make Color 12 min read
- 3 HSL vs HSV: Two Ways to Slice the Same Colors 3 min read
- 4 What Is OKLCH, and Why Are Browsers Switching to It? 2 min read
- 5 Why Print Colors Never Match Your Screen: CMYK Explained 3 min read
- 6 What Is Delta E? Measuring How Different Two Colors Really Are 2 min read
- 7 WCAG Contrast Ratios Explained: What AA and AAA Actually Require 2 min read
Put the theory into practice
Everything the guides explain is built into a free, live tool — try the math yourself.