Design Nomenclature / Color
Contrast of light and dark
Also called light-dark contrast, tonal contrast, luminance contrast, value contrast
Difference carried by value. It is the only contrast every viewer receives — colorblind, low-vision, in glare, in greyscale, at a distance — which is why accessibility standards are written in luminance terms and why hue difference alone has never satisfied one.
In practice
The workhorse. If a layout reads with the color thrown away, the value contrast is doing its job and the hue is free to do something else.
Not to be confused with
- Contrast of hueItten's simplest contrast: difference carried by hue alone, strongest between unmixed primaries. It is also the weakest tool for legibility, since hue difference without value difference vanishes for dichromats and in greyscale — two colors can be maximally opposed in hue and identical in value.
- Contrast of saturationDifference between a vivid color and a muted one of similar hue and value. The quietest of Itten's contrasts and the most useful in interfaces: a single saturated element in a toned field takes the eye without any change in value, so the page stays calm while still having a subject.