Colour theory is a crucial part of any designer's or artist's practice. For many, colour is such a pervasive part of everything we visually encounter in the world that it becomes an intuitive choice. Understanding how colour is formed and, more importantly, the relationships between different colours, can help you use colour more effectively in your designs, and make sure you pick the right palette for your projects.
If you think back to school, you'll probably recall being taught the basics of colour theory: there are three primary colours – red, yellow, and blue – and any colour can be created by mixing these three colours in varying quantities. It turns out that this isn't quite the whole story (although it's still workable enough to be taught to five-year-olds). In this guide, we'll walk through what you should know about colour theory, and explaining the jargon and design terms that come up along the way.
While you're here, you also might want to check out our guide to how to manage colours in Photoshop, or our guides to colour grading and art techniques. If you need software to put all this theory into practice, then we recommended you get Adobe Creative Cloud (opens in new tab).
Colour theory: A designer's guide
The Bauhaus school understood the power of colour in the 1920s and 1930s, with staff and students going on to develop colour theories for evoking particular moods and emotions through choice of palette in design and architecture. (Take a look at our guide to Bauhaus design (opens in new tab) for more on this.)
The theory of colour is a discipline that stretches back much further than that – at least to the 15th century – and uses physics, chemistry and mathematics to fully define and explain the concepts. However, much of this is unnecessary to being able to use colour effectively. Here, we're going to offer more of a handy overview of the most important aspects of colour theory you need to help you start making informed decisions in your own work.
Colour systems
A colour system is a method by which colour is reproduced. There are two primary colour systems: additive and subtractive (also known as reflective). We use both on a daily basis. Screens use additive colour to generate all the colours you see, while books and other print materials use subtractive colour for their front covers.
In simple terms, anything that emits light (such as the sun, a screen, a projector, and so on) uses additive colour, while everything else (which instead reflects light) uses subtractive colour.
01. Additive
Additive colour works with anything that emits or radiates light. The mixture of different wavelengths of light creates different colours, and the more light you add, the brighter and lighter the colour becomes.
When using additive colour, we tend to consider the building block (primary) colours to be red, green and blue (RGB), and this is the basis for all colour you use on screen. In additive colour, white is the combination of colour, while black is the absence of colour.
02. Subtractive
Subtractive colour works on the basis of reflected light. Rather than pushing more light out, the way a particular pigment reflects different wavelengths of light determines its apparent colour to the human eye.
Subtractive colour, like additive, has three primary colours – cyan, magenta, and yellow (CMY). In subtractive colour, white is the absence of colour, while black is the combination of colour, but it’s an imperfect system.
The pigments we have available to use don't fully absorb light (preventing reflected colour wavelengths), so we have to add a fourth compensating pigment to account for this limitation. We call this 'key', hence CMYK, but essentially it's black. Without this additional pigment, the closest to black we'd be able to render in print would be a muddy brown.
The colour wheel
In order to make it easier to see the relationship between different colours, the concept of the modern colour wheel was developed around the 18th century. Although colours exist on a continuous spectrum, it helped artists to break them down into individual blocks that could be named.
Colour wheels show the primary colours (conventionally red, yellow and blue in painting) on the outermost ring. The secondary colours are created by mixing two primary colours – if red, blue and yellow are the primary colours, the secondary colours are green, orange and violet. Tertiary colours are then created by mixing a primary with a secondary colour.
Note that using red, yellow and blue as the primary colours is not entirely accurate since greens and blues actually take up more of the colour spectrum. As a result, sometimes alternative colour wheels are used, such as red, blue and green, or cyan, magenta and yellow. It is possible to mix traditional primary colours with these alternative colour wheels, though they won't be as intense as pure pigments.
The colour wheel allows us to see at a glance which colours are complementary (opposite on the wheel), analogous (adjacent on the wheel), triadic (three colours positioned at 120 degrees on the wheel from each other) and so on (see below). Each of these relationships can produce pleasing colour combinations, and there are many more pleasing relationships between colours based on their position on the wheel.
Complementary colours
Complementary colours sit opposite each other on the colour wheel. These pairs have the highest colour contrast, so they often look very intense when placed next to each other. Two saturated complementary colours can sometimes clash and strain a viewer’s eyes, especially in close proximity, so it can be better to ensure that one of them is more neutral if you're going to use them together.
Mixing two complementary colours together produces a neutral grey, or even a black, as they cancel each other out. The greys in the centre of the colour wheel can be created in this way.
Analogous colours
Analogous colours sit next to each other on the colour wheel, so they have less colour contrast and therefore harmonise easily. In fact, sometimes they harmonise too easily, which means you might want to add contrast in these sorts of combinations, for example by pushing the tonal or saturation contrasts (or both).
When mixed together, analogous colours produce bright intermediary hues. The closer two colours are on the colour wheel, the more intense their mixture is. The further apart they are, the duller the mixture.
Triadic colours
Triadic schemes comprise three colours that are evenly spaced around the colour wheel. This type of scheme can be challenging if you're using saturated colours as it will include a large area of the wheel, which makes colour contrast hard to manage. One solution is to pick a dominant colour and let the other two support it as more subdued tones.
Another option is to tie a triad of saturated colours together with whites. This allows the eye a break and reflects subtle indications of the triad. Alternatively, triad colours can be used in small amounts to ‘spice up’ neutral arrangements.
Split complementary colours
Split complementary colour schemes are like complementary schemes, but in this case, one of the colours is split into two. The other colour sits opposite the centre point of this pair. The separation between the split pair can be narrow or can expand until it transforms into a triadic scheme.
This kind of scheme is a good option for a limited palette because it offers the harmony of a complementary colour scheme while covering more ground on the colour wheel and including a wider range of colours. Complementary schemes sometimes split both colours (this is sometimes called a tetradic scheme). They work especially well if the range of each pair is limited.
There are free apps for picking a colour scheme, or you could use your designer's eye to pick your own. Click through to the next page for a little help on this.
The three components of a colour
Yellow is yellow is yellow, right? Well, actually, no. There are many different colours we could refer to as yellow. Different shades or tints, saturations and hues are all possible while still being within the yellow part of the colour wheel. As a result, there are three primary component parts that help us define a colour: hue, saturation and brightness.
Hue
This is the position on the colour wheel, and represents the base colour itself. This is typically referred to in degrees (around the colour wheel), so a yellow colour will appear between 50 and 60 degrees, with the perfect yellow appearing at 56 degrees. Green, meanwhile, appears at 120 degrees on the wheel at so on.
Saturation
This is a representation of how saturated (or rich) a colour is. Low saturation results in less overall colour, eventually becoming a shade of grey when fully desaturated. Saturation is normally referred to as a percentage between 0 and 100%.
Brightness
This is how bright a colour is, typically expressed as a percentage between 0 and 100%. A yellow at 0% brightness will be black, while the same yellow hue and saturation at 100% brightness will be the full yellow colour.
Colour gamut
Colour gamut is a way of describing the full range of potential colours a system can reproduce. It may surprise you to learn that the range of colours achievable in CMYK is different to the range you can achieve with RGB.
This is partially because of the nature of the two different systems, but also (in the real world at least) as a consequence of limitations in our technology – screens aren’t always capable of producing the same range of colours as each other, and pigments reflect light at a non-uniform rate as you reduce their saturation.
Colour perception
It’s worth also looking at how different colours can affect the way we perceive other colours. A typical illustration of this features a mid-grey tone placed over a light grey background, and the same mid-grey tone shown over a dark grey background.
The apparent brightness of the mid-grey is altered according to the context in which you see it – a trick of the eye, working to make sense of its surroundings. Hues works in the same way as tones when placed adjacent to other colours, allowing you to create different effects using the same palette of colours.
The emotions of colour
Colour can play a vital role in how people feel when they see an image since certain colours tend to be associated with certain emotions. There are many complex reasons why a colour creates a psychological reaction in a viewer, and it depends on context, societal influences and interactions with other colours rather than the colour’s inherent properties alone.
A field of yellow flowers would be a bright, uplifting scene, but yellow is also associated with danger as it appears on warning signs and poisonous insects. As a result, some associations may seem contradictory, but it's worth bearing in mind how they can affect the way people feel.
RED = excitement, aggression, romance
YELLOW = warmth, friendliness, danger
GREEN = nature, sickliness, envy
BLUE = relaxation, coldness, grief
WHITE = cleanliness, innocence, emptiness
BLACK = oppressive, calm, powerful
Key
When it comes to painting, the key of an image is the dominant tonal value that it has overall, and how limited its tonal values are to a certain range. A high key composition is dominated by light tonal values. It will tend to omit or only minimally use dark tonal values, with more pastel colours dominating, while saturated colours act as colourful shadows. As a result, high key compositions often have a light, airy feel.
In contrast, low key compositions allow dark tonal values to predominate, and omit, or minimally use light tones. This can be good for creating atmospheric effects. The addition of small touches of light values creates dramatic tonal contrast.
Further reading
There's more to explore in the world of colour, which is why we've got a tag for all our articles on the subject of colour (opens in new tab). Read some of these highlights below.
01. A designer's guide to using colour in branding
What are the ‘right’ combinations of colours, and how can designers sidestep subjective debates to harness the power of colour more effectively in branding projects? We speak to experts in colour branding and look at tools to help you make the right choices. Read our designer's guide to using colour in branding (opens in new tab).
02. The best monitor calibrators
To ensure your monitor is displaying colours as accurately as possible, you need to make sure it's properly calibrated. This is essential for anyone who works with graphic design, video, photos or digital art – if your monitor isn't calibrated properly, you could be seeing a totally different colour to what your audience are seeing. This guide to the best monitor calibrators will help you find the right tool for the job.
03. Choose the right website colour palette
Get started picking the perfect colour scheme with help from this guide on how to choose the right colour palette for your website. It's a good introduction to the different things to consider when making your design decisions, with references to psychological studies and colour theory.
04. How to pick the perfect colours every time
The Colour Affects System identifies links between four colour groups and four basic personality types. If harnessed correctly, designers can use this system to kill subjective debate around colour in client meetings. This guide explains how.
05. Use colour to shape UX
When creating a site that resonates with your audience, your choice of colour can be surprisingly impactful. This article on how to use colour to shape UX takes an in-depth look at how you can use specific colours to build trust and increase revenue.
06. 10 colour management terms to know
Getting your colours right means getting your head around some tricky terms. There are a number of jargon terms that might baffle you, but this guide will help (opens in new tab). You'll soon be able to sort your spectrophotometer from your tristimulus colorimeter...
07. Outstanding uses of colour in branding
Successfully 'owning' a colour is a big deal. With this in mind, we've explored how different brands around the world have staked their respective claims to 10 colours – in some cases with considerable success. Explore these outstanding uses of colour in branding.
Read more:
- How to draw: Top drawing tutorials
- Essential watercolour techniques
- Golden ratio: A designer's guide
