Colour model Archives | lightcolourvision.org

Brightness & colour models

About brightness & colour models

The term brightness is often used in association with a specific colour model.
Examples of colour models include:
The HSB colour model uses the term brightness alongside hue and saturation.
Some colour models don’t use the term brightness at all, so when we change from one colour model to another it’s best to change our terminology as well.

Colour models

About colour models

A colour model derived from colour theory enables a more precise and reproducible method of representing and working with colour.

Colour models are a practical application of colour theory that establish terms, 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 seamless digital output to TVs, computers, phones, or printing onto paper and other surfaces.
Understanding colour models and utilizing them effectively can contribute to maintaining consistent and accurate colour reproduction across various media.
Widely used colour models include:
In addition to the colour models mentioned above, numerous other models are used in specific contexts, such as the Lab colour model employed in printing or the LCH colour model used in digital image processing.

A colour model is a framework that allows us to:

Make sense of colour in relation to human vision, the surrounding world, and various media and technologies.
Understand the relationship between different colours and their properties.
Mix specific colours from other colours to achieve predictable and desired results.
Specify colours using names, codes, notations, equations, and other forms of representation.
Organise and utilize colour for different purposes, such as design, visual arts, or scientific applications.
Use colours in consistent and repeatable ways across different platforms and media.
Develop systems and rules for blending and using different media, such as light, pigments, or inks.
Create colour palettes, define gamuts, and establish colour guides to guide artistic or design decisions.

Colour models and colour wheels

About colour models and colour wheels

Colour wheels are used to represent colour models that can generate a complete range (gamut) of colours using three primary colours. These models include:
- The RGB colour wheel
- The RYB colour wheel
- The CMY colour wheel
The spectral colour model, which represents individual wavelengths of light in the visible spectrum, is not typically explored using colour wheels.
- A diagram of the spectral colour model typically depicts its constituent colours in the form of a strip with red at one end and violet at the other.

Colour theories, models, spaces and management systems

About colour theories, models, spaces and management systems

Colour theory, colour models, colour spaces, and colour management systems are integral to understanding, representing, and manipulating colour in various fields.

Colour Theory

A colour theory is a set of principles and concepts used to understand how colour works, how colours relate to each other, and how they are perceived or interpreted by the human eye. A colour theory allows us to predict in advance how colour behaves in practice.

Colour Model

A colour model is a practical application of colour theory. In both industrial and design contexts a colour model is and mathematical representation or system for creating a full range of colours using a set of primary colours. Examples include the RGB (Red, Green, Blue) model for light-based colours and the CMY (Cyan, Magenta, Yellow) model for pigment-based colours. The choice of a colour model depends on the medium (light, paint, ink, etc.) and the application (canvas, monitor, printer, etc.).

Colour Space

A colour space is a specific organization of colours derived from a colour model. It can be used to define a gamut or subset of colours that can then be successfully applied within a particular context or for a specific purpose. Examples of colour spaces used in digital design include sRGB and Adobe RGB within the RGB model, each of which encompasses a different range of colours.

Colour Management System

These are systems or protocols designed to ensure consistent and accurate colour reproduction across different devices, media, and lighting conditions. They consider the specifications of the devices used to capture, edit, or display colour, as well as the lighting conditions in which colours are viewed.

In summary, a colour theory provides the underlying concepts, a colour model provides a framework to represent these concepts, a colour space defines a specific range of colours that can be generated within the parameters of the model, and a colour management system ensures consistency and accuracy in reproducing colours across different contexts and devices.

Hue and colour models

About hue and colour models

Hue refers to the attribute of a colour that allows us to distinguish it from others on the colour spectrum, and it is a fundamental concept in colour theory.
Different colour models define hue in slightly different ways and associate it with different families of terms, so it is best to associate it with a specific colour model to avoid confusion.
For example:
- The RGB colour model works in practice by asking three questions of any colour: how red is it (R), how green is it (G), and how blue is it (B).
- The HSB color model defines a colour by its hue (H), measured in terms of an angle between 0° and 259° on a colour wheel, and then determines its saturation (S) and brightness (B).
Examples of colour models include:
Examples of practical applications include digital design, stage lighting, and the mixing of oil or water-based paints, inks and dyes.

Why use colour models

About why we use colour models

Colour models help to relate and coordinated colours with one another when working with different light sources, media such as paints or inks, objects and materials.
Colour models clarify the ways in which coloured lights, transparent inks and opaque paints (etc.) all produce different results when mixed.
Colours models help us manage the fact that colours behave and appear differently:
- When emitted by different types of light sources.
- Depending upon the type of media – inks, dyes, pigments.
- When seen or used in different situations (indoors, in sunlight, in low light, on a digital display etc.)
- When applied to, mixed with, or projected onto different materials.
- When used for different purposes (fabrics, electrical wiring and components, print media, movies etc.)