In the digital realm, we can describe colour in terms of hue, saturation, and brightness by setting each on a scale, typically from 0 to 100 (a familiar scale to humans) or 0 to 255 (familiar to computers). But what exactly does this scale refer to? We could fire the electron guns in a CRT monitor in the proportions directly dictated by our HSB values, but the progression through the scale might be quite uneven, and the result would be different on each monitor.