- 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 difference between the RGB and HSB colour models is limited to the way colours are represented in terms of colour notation and dealt with in software and apps.
- Both the HSB and RGB colour models deal with how to mix red, green and blue light to produce other colours.
- HSB is popular because it provides an intuitive way to select and adjust colours when using applications such as Adobe Creative Cloud for design, photography or web development.
- The HSB colour model is popular because it provides an intuitive way to select and adjust colours in software applications used for graphic design, web development and photography.
- 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.
- Both the RGB and HSB colour model can be used to describe any colour on a TV, computer or phone.
In the HSB colour model:
- 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%).
- A fully saturated colour is produced by a single wavelength or a narrow band of wavelengths.
- On HSB colour wheels, saturation is usually shown to increase from the centre to the circumference.
- Brightness (colour brightness) refers to the difference between the way a colour appears to an observer in well-lit conditions compared with its subdued appearance when in shadow or when poorly illuminated.