Colour spaces


Martin McBride, 2021-04-25
Tags colour cmyk hsl greyscale luminance chrominance
Categories computer science colour

As we saw in the previous section, colour is essentially a 3 dimensional quantity. It can be represented by 3 values, red, green and blue. Each unique combination of red, green and blue creates a unique colour.

You could think of these values as axes in a 3 dimensional space, where each point in space is a particular colour. We call this space the RGB colour space.

There are other ways to represent colours. They typically use 3 values, but rather than red, green and blue they use a different set of values (we call this a different colour space). Here are the main ones

  • RGB as described above
  • Greyscale images only contain shades of grey, with no colour (like black and white photographs).
  • CMYK colour spaces are used in printing, where cyan, magenta, yellow, and black inks are used to create colours.
  • HSL (hue, saturation, lightness) colour spaces represents a colour as a hue (that represents the basic, underlying colour), saturation (that represents how pure the colour is), and lightness (how light or dark the colour is).
  • Luminance/chrominance colour spaces represents colours using a brightness component, and two other values that represent chromatic (colour) component.
If you found this article useful, you might be interested in the book Computer Graphics in Python or other books by the same author.

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