Learn About Color

Short, plain-language guides to how color works — each paired with a free game to feel it, not just read it.

Color perception is a trainable skill, not fixed talent, and these guides are built to grow it. Each one explains a single idea in plain language — from hue and contrast to how the eye itself works — and points you to a matching daily game so you can feel the effect, not just read about it. Everything here is free; a Personal Pass only adds optional progress tracking, and the education tools let a teacher assign a game with a single link.

Color basics

• Hue, saturation & lightness explained — The three dials — hue, saturation and lightness — that describe any color and let you change one without disturbing the others.
• RGB & hex color codes explained — How screens build color from red, green and blue light, and what a hex code like #3A7BD5 actually says.
• Color temperature: warm vs cool (Kelvin) — Why some colors feel warm and others cool, and how the Kelvin scale puts numbers to that feeling.
• Color harmony: complementary, analogous & triadic — The classic recipes — complementary, analogous and triadic — for picking colors that sit well together.

Contrast & accessibility

• Color contrast explained: WCAG 4.5:1, 3:1 & 7:1 — What the WCAG contrast ratios mean, and how to reach 4.5:1 so text stays easy to read for everyone.
• Color vision differences: an awareness guide — A plain-language look at how color vision varies from person to person, and how to design with that in mind.

How color perception works

• How your eyes see color: cones & trichromacy — Inside the eye: the three cone types whose overlapping signals give us trichromatic color vision.
• How many colors can humans see? — Where the famous 'millions of colors' figure comes from — and why the honest answer is fuzzier.
• Delta-E & the just-noticeable color limit — How Delta-E turns the gap between two colors into a single number, and marks the smallest step you can reliably see.
• Color afterimages: why you see the opposite — Stare, then look away: why a floating opposite color appears, explained by the opponent-process idea.
• Color midpoints: the color halfway between two — What 'halfway between two colors' really means, and why your eye and the math don't always agree.
• Color memory: why exact shades are hard to recall — Why you can recognise a shade at a glance yet struggle to recall it exactly a minute later.

Color theory for artists & designers

• Color wheel relationships: how designers pick hues — How the color wheel becomes practical palettes, and the relationships designers reach for first.
• Simultaneous contrast: why colors shift in context — The same color looks different on different backgrounds — the effect that catches out every beginner.
• Value & saturation: the backbone of composition — Why value and saturation, even more than hue, decide whether a composition holds together.
• How to build a color palette: 60-30-10 & beyond — A step-by-step method, including the 60-30-10 rule, for building palettes that feel balanced.

Teaching color perception

• Teaching color perception: a teacher's handbook: How the color games map to classroom skills, with a game-by-skill matrix and notes on color-vision differences.
• Color perception lesson plans: Ready-to-teach sessions by age group, from color mixing to contrast accessibility, each built around a free classroom game.
• Assessment rubrics for color skills: Low-stakes formative rubrics for matching accuracy, shade discrimination, harmony and contrast awareness.

Play the daily color games

Ready to try your eye? Start with today's Huekle games. Also explore our sister sites for the ear and for timing: Hearkle (pitch) and Chronkle (tempo).