Greyscale colour space

Martin McBride, 2021-04-28
Tags colour greyscale
Categories computer science colour

Any RGB colour that has equal amounts of red, green and blue, will display as a shade of grey, for example:

  • rgb(0%, 0%, 0%) is black.
  • rgb(30%, 30%, 30%) is dark grey.
  • rgb(100%, 100%, 100%) is white.

In the greyscale colours space, the colour is specified by a single value. The colour is displayed as if the red, green and blue values were all equal. You can think of greyscale as a subset of RGB that includes only the pure grey colours.

The greyscale colour space can only show shades of grey. It is useful for images that don't include any colour, for example:

  • Text only documents.
  • Charts and diagrams that don't use colour.
  • Scans of black and white photographic images.

This image

A greyscale image only stores 1 value per pixel (the grey level), whereas an RGB image store 3 values per pixel.

If you found this article useful, you might be interested in the book Computer Graphics in Python or other books by the same author.


Popular tags

2d arrays abstract data type alignment and animation arc array arrays behavioural pattern bezier curve built-in function callable object chain circle classes close closure cmyk colour combinations comparison operator comprehension context context manager conversion count creational pattern data types design pattern device space dictionary drawing duck typing efficiency ellipse else encryption enumerate fill filter font font style for loop function function composition function plot functools game development generativepy tutorial generator geometry gif gradient greyscale higher order function hsl html image image processing imagesurface immutable object index inner function input installing iter iterable iterator itertools l system lambda function len line linear gradient linspace list list comprehension logical operator lru_cache magic method mandelbrot mandelbrot set map monad mutability named parameter numeric python numpy object open operator optional parameter or partial application path pattern permutations polygon positional parameter print pure function python standard library radial gradient range recipes rectangle recursion reduce repeat rgb rotation scaling sector segment sequence setup shape singleton slice slicing sound spirograph sprite square str stream string stroke structural pattern subpath symmetric encryption template text text metrics tinkerbell fractal transform translation transparency triangle tuple turtle unpacking user space vectorisation webserver website while loop zip