Misconception: Black and white and grey are not colours
Concept Corrected: Blacks, whites, and greys are all colours
Colours have more than one perceptual attribute, but sometimes people confuse the terms colour and hue to mean the same thing. Hue identifies the family to which a colour belongs. Examples of hues include green, red, yellow, and blue. Other parameters used to fully describe the appearance of colours include lightness/value, which describes how pale or dark a colour appears, and chroma, which describes how vivid or muted a colour appears.
Blacks, whites and greys are the achromatic colours. They lack two colour attributes - chroma and hue - but they are indeed colours!
We need to be aware of all the ways to describe colours, to recognize that blacks, whites and greys are all in fact colours.