RYB Subtractive Colour Model


This diagram introduces the RYB colour model. It shows the three primary colours (red, yellow and blue) with secondary colours between them.

The RYB colour model is a subtractive colour model that predicts the appearance of red, yellow and blue paints and opaque pigments when they are mixed together to produce other colours.

What you need to remember:

  • The RYB colour model is a method for mixing different artists paints and opaque pigments to produce other colours. It is called a subtractive colour model (a subtractive approach to colour).
  • The name of the RYB colour model comes from the initials of its three primary colours – red, yellow and blue.
  • When paints corresponding with the red, yellow and blue primary colours are mixed together they combined to produce other colours.
  • Secondary colours are the colours produced when pairs of primary colours are combined in equal proportions. The RYB secondary colours are orange, green and purple.
  • If paint corresponding with all three subtractive primary colours are mixed together in matching proportions the result is a dark brown or black.
  • If paint corresponding with all three subtractive primary colours are mixed in unequal proportions then many thousands (or possibly millions) of colours can be produced.
  • The RYB colour model does not define the precise colour of the red, green and blue primaries.
  • When the exact composition of primary colours is defined, the colour model then becomes an absolute colour space.


RYB Subtractive Colour Model

Red, yellow and blue are the three primary colours used with the RYB colour model.
Both are subtractive colour models. Subtractive colour models such as CMY or RYB are used for mixing paints, pigments, inks and dyes.
A subtractive colour model helps to make sense of what happens when different coloured pigments (eg. paints, inks, dyes or powders) are mixed together to produce other colours.

About the diagram

About the diagram
What you need to remember:
  • A diagram of spectral colour is usually presented in the form of a continuous linear spectrum organised by wavelength, with red at one end and violet at the other.
  • The best known spectral colours are the colours of the rainbow – red, orange, yellow, green, blue and violet.
  • All spectral colours are produced by a single wavelength of light.
  • The fact that we see distinct bands of colour in a rainbow, rather than a continuum of colours, is an artefact of human colour vision.
  • Every spectral colour is produced by a single wavelength of visible light – the small part of the electromagnetic spectrum that our eyes are attuned to.
  • Spectral colours are produced as raindrops and other transparent media refract and disperse white light causing the different wavelengths to fan out into an array of colour.
  • All transparent media refract and disperse light without causing scattering.
  • Spectral colour is neither an additive nor subtractive colour model because each colour is produced by a single wavelength rather than by mixing different colours.
  • Sunlight produces the full range of spectral colours because at the point at which light is emitted by the sun and propagates through the vacuum of space, it contains all wavelengths of visible light.
  • Light containing all the wavelengths of the visible spectrum is called white light.
Spectral and RGB colours

Spectral colour should not be confused with RGB colour:

  • Spectral colours are components of the visible spectrum.
  • RGB colours are produced by mixing wavelengths of light corresponding with the three additive primary colours – red, green and blue.
  • A diagram of RGB colour is often represented in the form of a colour wheel and shows the colours produced by mixing adjacent colours on the wheel.
What is a colour model?

A colour model is a way of:

  • Making sense of the colours we see around us in the world.
  • Understanding the relationship of colours to one another.
  • Understanding how to mix each type of coloured media to produce predictable results.
  • Specifying colours using names, codes, notation, equations etc.
  • Organising and using colours for different purposes.
  • Using colours in predictable and repeatable ways.
  • Working out systems and rules for mixing and using different types of colour.
  • Creating colour palettes, gamuts and colour guides.
Why use colour models?
  • Colour models help to relate colours to:
  • Colour models make sense of the fact that coloured lights, transparent inks and opaque paints (etc.) all produce different results when mixed.
  • Colour models help us manage the fact that colours mean and feel different and have different associations depending on context.
  • Colours models help us manage the fact that colours behave and appear differently:
    • When emitted by different types of light source.
    • When applied to, mixed with, or projected onto different materials.
    • When used for different purposes (fabrics, electrical wiring and components, print media, movies etc.)
    • When seen or used in different situations (indoors, in sunlight, in low light, on a digital display etc.)
Additive and subtractive colour

There are two principal types of colour model, additive and subtractive. Additive colour models are used when mixing light to produce colour. Subtractive colour models are used for printing with inks and dyes. The most common colour models used by graphic designers on a day to day basis are the RGB model on their computer displays and the CMYK model for digital printing.

Remember that:
  • Seeing colour results from how our eyes process light waves.
  • In the real world, colours are changing all the time, appear differently in different situations and are infinitely variable.
  • So colour models help to make sense of a chaotic world.
What colour models do?

A colour model helps to do any of the following:

  • Decide what colours to mix to get the colour you want.
  • Know what happens when you mix two or more colours together.
  • Provide a name or code for a colour or a series of colours you want to use again.
  • Give you a list of colours produced by a rainbow or by a digital display.
  • Provide a system to mix a palette of colours from red, green and blue (RGB) or from cyan, magenta and yellow (CMY).
Spectral colour model

The spectral colour model (red, orange, yellow, green, blue, violet) is associated with rainbows and the refraction and dispersion of wavelengths of light into bands of colour.

RGB colour model

RGB (red, green, blue) is an additive colour model based on the trichromatic theory of colour vision. It is widely used in video cameras, for producing colour on digital screens and with software such as Adobe Creative Cloud.

CMY(K) colour model

CMY (cyan, magenta, yellow) is a subtractive colour model. It is the standard colour model for digital printing. Printers often include a fourth component, black ink (K), to increase the density of darker colours and blacks.

HSB colour model

HSB (hue, saturation, brightness) is a popular colour model because it is more intuitive and so easier to use when adjusting colour with digital software such as Adobe Creative Cloud.

HSB is one of a family that also includes HSV (hue, saturation, value) and HSI (hue, saturation, intensity).

Applications of colour models

Colour models have many applications including:

  • Understanding colour vision.
  • Mixing different coloured media eg. lights, paints, inks and dye.
  • Using colour with different equipment and technologies.
  • Storing and sharing colour information eg. notation systems and file types.
  • Describing and naming colours in a consistent way.
  • Nomenclature for describing similar things eg. systems for describing birds according to their colour.
  • Comparing colours eg. swatches and samples.
Colour models, colour spaces and colour systems
  • Colour models are device-dependent. This means that a colour specified as R=220, G=180, B=140 might appear differently on two digital monitors or when printed by different printers with the same specifications. In other words, the exact colour produced depends on the device that produces it not on the colour model itself.
  • A colour space describes the range of colours that an observer might see. Colour spaces can be very limited when a photo is printed on a low price digital printers, large when the same image is viewed on a high definition digital displays, or huge when the original scene is viewed in bright sunlight on a summer day.
  • A colour system considers all the factors that affect the observer, the colour model, how information is encoded before sending to the output device and the circumstances in which it is expected to be viewed.

Some key terms

A colour model is the how-to part of colour theory. Together they establish terms and definitions, rules or conventions and a system of notation for encoding colours and their relationships with one another.

A colour model is a way of:

  • Making sense of the colours we see around us in the world.
  • Understanding the relationship of colours to one another.
  • Understanding how to mix each type of coloured media to produce predictable results.
  • Specifying colours using names, codes, notation, equations etc.
  • Organising and using colours for different purposes.
  • Using colours in predictable and repeatable ways.
  • Working out systems and rules for mixing and using different types of colour.
  • Creating colour palettes, gamuts and colour guides.

A subtractive colour model combines different hues of a colourant such as a pigment, paint, ink, dye or powder to produce other colours.

  • CMYK is a subtractive colour model.
  • CMYK pigments are the standard for colour printing because they have a larger gamut than RGB pigments.
  • CMYK printing typically uses white paper which has good reflective properties and then adds cyan, magenta, yellow and black ink or toner to produce colour.
  • Highlights are produced by reducing the amount of coloured ink and printing without black to allow the maximum amount of light to reflect off the paper through the ink.
  • Mid tones rely on the brilliance and transparency of the pigments and the reflectivity of the paper to produce fully saturated colours.
  • Shadows are produced by adding black to both saturated or desaturated hues.

The trichromatic colour model is a theory of colour that establishes terms, rules and methods to enable human colour vision to be dealt with in both systematic and practical ways.

Primary colours are a set of colours from which others can be produced by mixing (pigments, dyes etc.) or overlapping (coloured lights).

  • The human eye, and so human perception, is tuned to the visible spectrum and so to spectral colours between red and violet. It is the sensitivity of the eye to the electromagnetic spectrum that results in the perception of colour.
  • A set of primary colours is a set of pigmented media or coloured lights that can be combined in varying amounts to produce a wide range of colour.
  • This process of combining colours to produce other colours is used in applications intended to cause a human observer to experience a particular range of colours when represented by electronic displays and colour printing.
  • Additive and subtractive models have been developed that predict how wavelengths of visible light, pigments and media interact.
  • RGB colour is a technology used to reproduce colour in ways that match human perception.
  • The primary colours used in colour-spaces such as CIELAB, NCS, Adobe RGB (1998) and sRGB are the result of an extensive investigation of the relationship between visible light and human colour vision.

ROYGBV is an acronym for the sequence of hues (colours) commonly described as making up a rainbow: red, orange, yellow, green, blue, and violet.

  • A colour wheel is a circular diagram divided into segments, featuring primary colours, and used to visualize the result of colour mixing.
  • Colour wheels can enhance understanding of colour relationships and assist with the accurate selection and reproduction of colours.
  • A colour wheel starts with segments representing primary colours. Additional segments are added between them to explore the outcome of mixing adjacent primary colours.
  • By adding more segments between existing ones, further mixing of adjacent colours can be explored.
  • A colour wheel exploring the additive RGB colour model starts with red, green, and blue primary colours.
  • A colour wheel exploring the subtractive CMY colour model starts with cyan, magenta, and yellow primary colours.

Diagrams are free to download

Downloads: Slides or Illustrations

  • SLIDES are optimized for viewing on-screen.
  • ILLUSTRATIONS are optimized for printing on A4 pages in portrait format.
  • Slides are available in JPG and AI (Adobe Illustrator) file formats.
  • Titles: Slides have titles.
  • Backgrounds: Black.
  • Size: 1686 x 1124 pixels (3:2 aspect ratio).
  • Illustrations are available in JPG and AI two file formats.
  • Titles: No titles.
  • Backgrounds: White.
  • Size: 1686 x 1124 (3:2 aspect ratio). So all illustrations reproduce at the same scale when inserted into Word documents etc.
  • Labels: Calibri 24pt Italic.

File formats: JPG & AI

  • JPG (JPEG) diagrams are 1686 x 1124 pixels (3:2 aspect ratio).
  • If a JPG diagram doesn’t fit your needs, you can download it as an AI (Adobe Illustrator) file and edit it yourself.
  • JPG files can be placed or pasted directly into MS Office documents.
  • All AI (Adobe Illustrator) diagrams are 1686 x 1124 pixels (3:2 aspect ratio).
  • All our diagrams are created in Adobe Illustrator as vector drawings.
  • Save as or export AI files to other formats including PDF (.pdf), PNG (.png), JPG (.jpeg) and SVG(.svg) etc.

Spelling: UK & US

We use English (UK) spelling by default here at lightcolourvision.org.

  • After copy/pasting text please do a spell-check to change our spelling to match your own document.
  • Download AI versions of diagrams to change the spelling or language used for titles, labels etc.
  • We are adding American English (US) versions of diagrams on request. Just contact us and let us know what you need.
  • When downloading JPG versions of diagrams, look out for JPG (UK) or JPG (US) in the download dialogue box.

Download agreement


Light, Colour, Vision & How To See More (https://lightcolourvision.org) : Copyright © 2015-2022 : MediaStudies Trust.

Unless stated otherwise the author of all images and written content on lightcolourvision.org is Ric Mann.


No part of this website may be copied, displayed, extracted, reproduced, utilised, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical or otherwise including but not limited to photocopying, recording, or scanning without the prior written permission of MediaStudies Trust.


Exceptions to the above statement are made for personal, educational and non-profit purposes:

Before downloading, cutting and pasting or reproducing any information, images or other assets found on lightcolourvision.org we ask you to agree to the following terms:

  1. All information, images and other assets displayed and made available for download on the lightcolourvision.org website are copyright. This means there are limitations on how they can be used.
  2. All information, images and other assets displayed or made available for download are solely and exclusively to be used for personal, educational and non-profit purposes.
  3. When you find the resources you need, then part of the download process involves you (the user) ticking a box to let us (at lightcolourvision.org) know we both agree on how the material can be used.
  4. Please contact kiaora.lightcolourvision@gmail.com before considering any use not covered by the terms of the agreement above.

The copyright to all information, images and all other assets (unless otherwise stated) belongs to:

The Trustees. MediaStudies Trust
111 Lynbrooke Avenue
Blockhouse Bay
Auckland 0600
New Zealand

We love feedback

Your name and email address will be used solely to provide you with information you have specifically requested. See our privacy policy at https://lightcolourvision.org/privacy/.

We welcome your feedback 🙂

    Note: The feedback form records the URL of the current page

    Thank you so much for your time and effort