Hue

Hue refers to the perceived difference between one colour and another by using names such as red, yellow, green or blue.

About hue and colour models
  • To avoid confusion about the term hue, it is best to associate it with a colour model, a practical application and a family of related terms.
  • Examples of colour models include spectral colour, RGB colour, CMYK colour and HSB colour.
  • Examples of practical applications include digital design, stage lighting, mixing of oil or water-based paints, inks and dyes.
About seeing in colour
  • When an observer asks themselves what colour something is, they might refer to:
    • Spectral colours and use names commonly associated with rainbows (ROYGBV)
    • A specific colour model such as RGB, CMYK or HSB
    • A family of colours such as warm or cool colours
    • Tints or shades of colours
    • A  palette of colours they have selected or are working with.
  • Some people are able to refer to a broader vocabulary of colour names such as dark red, vermilion, golden yellow, lemon yellow, pale yellow, greenish-yellow, chartreuse, leaf green or light green.
About colour models
  • A colour model derived from a colour theory enables a more exact and reproducible approach to colour.
  • Colour models are the how-to part of colour theory. Together they establish terms and definitions, rules or conventions and systems of notation for encoding colours and their relationships to one another.
  • These days, the most practical colour models are built into applications such as Adobe Creative Cloud and allow easy digital output to TV’s, computers and phones or printing onto paper and other surfaces.
  • Widely used colour models include:
About using the term hue here at lightcolourvision.org
  • At lightcolourvision.org we use hue in relation to the colour models it belongs to. One of our favourites is the HSB colour model.
  • Colour models describe the attributes of colour in different ways.
  • The HSB colour model refers to hue alongside saturation and brightness.
  • The HSB colour model is extensively used for digital design and can be used to describe any colour on a TV, computer or mobile phone.
  • The CMYK colour model uses a different set of attributes because one of its main concerns is how coloured inks appear on paper. Because hue isn’t part of the vocabulary used in that field the term is best avoided.
About the HSB colour model

The HSB colour model is an additive colour model used to mix light. Subtractive colour models are used to mix pigments and inks.

  • The only difference between the RGB and HSB colour models is 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 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 accounts for colour names such as red, yellow, green or blue.
    • Hue can be measured as a location on the standard colour wheel and expressed in degrees between 0 and 360.
  • 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.
    • As the brightness of a fully saturated hue decreases it appears progressively darker.
    • Brightness is measured as a percentage from 100% to 0%.