Quantitative Color Scales

The Desired Properties of a Quantitative Color Scale

A quantitative color scale is designed to represent quantitative information. It has 2 main properties: uniformity and discriminability.

Uniformity

This means that the color scale must be perceptually uniform i.e. value difference = perceived difference

To create a uniform color scale, we must start with a single hue/color and then uniformly vary the luminance/lightness, keeping the saturation constant.

Discriminability

This refers to being able to represent as many distinct values as possible by having as many distinct colors as possible.

Multi-Hue Color Scale

The previous subsection depicted a single hue color scale. We can also use multi-hue color scales, starting with a dark color and ending with a light color, with several other hues in the middle, in uniformly increasing order of lightness.

Some common reasons to use multi-hue color scales:

• aesthetics

• a larger set of colors increases discriminability

• allows us to communicate two types of information at once: we can depict quantity and also perform segmentation into regions that can be easily labeled (ex. the red region, the blue region, the yellow region etc.)