Colour scheme generator
Every scheme is one addition to the hue. This one shows the addition, and then tells you which of the colours you can actually read. Nothing you choose here leaves your browser — it is worked out on your own device, so there is nothing to send and nothing to log.
A scheme is one subtraction
Every colour scheme on every colour-theory site is the same operation: take the hue, add something to it, keep the saturation and lightness. That is the whole of it.
| Complementary | +180° |
|---|---|
| Analogous | −30°, +30° |
| Triad | +120°, +240° |
| Split complementary | +150°, +210° |
| Square | +90°, +180°, +270° |
| Tetrad | +60°, +180°, +240° |
| Monochromatic | the hue does not move; the lightness does |
Which is worth knowing, because it means a scheme generator has no opinion about colour at all. It is arithmetic on an angle.
And it says nothing about whether you can read it
Take the triad of pure red. You get red, green and blue — three colours with identical HSL lightness of 50%. Their contrast against white:
| #FF0000 | 4.00:1 | fails AA for ordinary text |
|---|---|---|
| #00FF00 | 1.37:1 | effectively invisible |
| #0000FF | 8.59:1 | passes AAA |
A factor of six, between colours the wheel calls equivalent. Green is the worst offender because green carries about 71% of what the eye reads as brightness, so a saturated green is nearly as bright as white.
That is why this page rates every colour it gives you against black and white. A palette you cannot read is not a palette, and no amount of harmony on the wheel fixes it.
What this cannot do
It cannot tell you whether a scheme looks good. Colour harmony is a matter of taste, culture and context, and the wheel is a rough heuristic that happens to be easy to compute rather than a law of perception.
It also works entirely in sRGB, which is the colour space of ordinary screens. Perceptually uniform spaces — Lab, OKLCH — do a better job of "equally spaced" and are a different page.