- Saturation (colour saturation) refers to the perceived difference between one colour and another in terms of purity.
- A saturated colour is a pure, unique spectral colour produced by a single wavelength (or a narrow band of wavelengths) of light.
- A fully saturated colour (100%) is the purest version of a hue.
- Unsaturated colours appear dull and washed out until their hue disappears leaving only monochromatic grey tones.
About saturation & wavelength
- A colour appears saturated when it is produced by a single (or narrow range) of wavelengths.
- A colour produced by a single wavelength of light is often referred to as pure spectral colour.
- Unsaturated colours appear washed out because they contain a broader range of wavelengths.
- Saturation is related to light complexity.
- Light complexity refers to the arrangement of wavelengths of light used to produce a colour.
- Bands of colour are composed of a continuous range of wavelengths.
- Spectral colours are composed of a single wavelength of light (or a narrow band of wavelengths).
- Non-spectral colours are produced by additive mixtures of wavelengths of light and so are the most complex.
- In real life, colours are produced by very complex mixtures of wavelengths. The greater number and spread of wavelengths across the visible spectrum, the lower the saturation of a colour.
About saturation and colour models
- The term saturation is best understood when associated with a specific colour model.
- Examples of colour models include:
- The HSB colour model uses the term saturation alongside hue and brightness.
- Some colour models don’t use the term saturation at all.
- When we change from one colour model to another, it’s best to change our terminology as well.
About the HSB colour model
The HSB colour model provides an alternative representation of the RGB colour model and provides a more intuitive way to select and adjust colours in software applications used for graphic design, web development and photography.
Both RGB and HSB are additive colour models. But whilst RGB relies on adjusting the amount of red, green and blue needed to produce other colours the HSB colour model relies on adjusting hue, saturation and brightness.
- Hue refers to the perceived difference between one colour and another and is usually described by using names such as red, yellow, green or blue.
- Hue can be measured as a location on an HSB colour wheel and expressed as a degree between 00 and 3600.
- Saturation refers to the perceived difference between one colour and another in terms of vividness.
- Saturation is measured between a fully saturated colour (100%) and an unsaturated colour that appears dull and washed out until all colour disappears leaving only a monochromatic grey tone (0%).
- On many HSB colour wheels, saturation increases from the centre to the edge.
- Brightness refers to the perceived difference between a colour observed in ideal sunlit conditions compared with conditions where the vitality of the hue is lost because the lighting is poor.
- Brightness can be measured as a percentage from 100% to 0%. As the brightness of a fully saturated hue decreases it appears progressively darker and achromatic.