Colour plays a pivotal role in print. It’s a powerful communication tool, helping us make decisions, generate emotional responses and better understand our world. But colour theory is both a science and an art that can take print aesthetics one step further.

Colour theory provides a logical structure for organising, combining, and mixing colours. For humans, our eyes and brains work together to translate light into colour. Light travels to the retina at the back of the eye, covered in light-receptive cells. When these cells detect light, they combine the information and send it along the optic nerve. The brain will then help us distinguish individual colours for us to interpret. While terminology surrounding colour has existed since Ancient Greece, polymath Sir Issac Newton was the first to formalise colour theory. He proved that light consists of separate colours by conducting experiments that refracted light through a glass prism. His work provided a foundation for the colour wheel we know today - an illustration depicting individual colours and their relationship with others in the spectrum (above). Most colour wheels are divided into 12 visible colours, and we divide them into three main categories:

 

Primary Colours

Red, Yellow, and Blue are colours from which other colours are made when mixed. You cannot create primaries by mixing other colours together. 

Secondary Colours

Green, Orange, and Purple are colours made by mixing two primaries. Yellow and Blue make Green, Red and Yellow make Orange and Red and Blue make Purple.

Tertiary Colours

Mixing a primary and secondary colour creates a tertiary colour, giving some hues a two-word name, such as Blue-Green and Red-Violet. These are also known as intermediate colours.

The colour wheel can then be further divided into colour harmonies:

Complementary Colours

Complementary Colours appear opposite each other on the colour wheel. For example, Yellow and Purple are intense hues that can compete with or enhance each other to create a harmonious colour palette.

Analogous Colours

Analogous Colours appear next to one another on the colour wheel. Red, Dark Orange, and Light Orange, is an example of an analogous colour pallette. When used together, they have a striking visual impact, and often, one colour, like Red, will dominate while the other two act as accents.

Triadic Colours

Triadic Colours are a group of equally spaced colours on the colour wheel, forming a triangle. For example, primary colours and secondary colours are triadic colours. Like Analogous Colours, one colour will tend to dominate while the other two serve as accents, giving printed artwork a visual ‘balance’.

Tetradic Colours

Tetradic Colours employ two sets of complementary colours, forming a rectangle shape on the colour wheel. They’re also known as Rectangle or Double Complementary Colours. They provide bold and vibrant colour schemes, and one colour will tend to dominate while the others act as accents.

Square Colours

Square Colours consist of four evenly spaced colours around the colour wheel, forming a square. This colour scheme creates rich, evocative designs, providing a cohesive balance of warm and cool colours. But more on that later.

Split Colours

Split Colours, or Split Complementary Colours, employ a single base colour and the two on either side of its complement, forming a ‘Y’ shape on the colour wheel. It creates a colourful equilibrium that is more understated than traditional, complementary colours.

Monochromatic Colours

Monochromatic literally means one colour, deriving from the Ancient Greek terms ‘mono’ (‘only’, ‘single’, ‘alone’) and chromatic (‘colour’). This colour scheme employs a single colour and varying shades and tints. It has a low contrast and can make print work look sleek and polished.

 

You can see these colour harmonies and more in practice using Adobe’s Colour Wheel tool.


Next, we need to establish how we see colours in print...

 

Additive Colour Theory vs Subtractive Colour Theory

Additive Colour Theory denotes colour is made with light. Adding more colour makes a colour appear lighter. The additive colour primaries are Red, Green and Blue. This colour model is known as RGB, which we use for viewing colours on screens like computer monitors. Red, Green and Blue combined create white light. But by manipulating the light wavelengths that produce the primaries, we add colours, thus creating a colour spectrum. 

Every pixel on a screen emits light, and when lights possessing different wavelengths are combined, the waves interfere with each other, enhancing and/or cancelling each other out. Each wavelength depicts a different colour. For example, Blue light plus Green light (with no Red) produces Cyan; Red light plus Blue light (with no Green) produces Magenta; Red light plus Green light (with no Blue) produces Yellow.

Subtractive Colour Theory denotes how colour appears when applied to a semi-absorbent surface like paper. The subtractive colour primaries are Cyan, Magenta and Yellow, which we use in print. Coloured substances like ink absorb varying levels of light and specific wavelengths that impart their colour. The more added colour, the greater the number of lightwaves and the darker a colour becomes. Electronic devices with screens emit light, but a white piece of paper reflects it and, therefore, reflects every wavelength of light to produce colour. Cyan and Magenta combined reflect Blue light, Magenta and Yellow combined reflect Red light and Yellow and Cyan combined reflect Green light. So RGB and CMY work oppositely to each other, and we can create a wider variety of colours by subtracting the values of the primaries and printing with black ink (K) to get a variety of shades. 

Dive deeper into RGB and CMYK Colour profiles here or watch this quick video guide.

 

Black and White (Greyscale) Printing

Creating black and white colours depends on whether you work with an additive (light-based) or a subtractive (ink-based) colour. In the physical world, black isn’t present in the visible colour spectrum. All other colours are a reflection of light, except for black, because according to science, black is the absence of light. However, some argue that white is a colour because it contains all the colours in the visible light spectrum. This theory can also be applied to black, as combining all pigments makes this colour. But black images printed on a white page contain an ink pigment, which is subtractive. So, if you’re printing any of your projects in greyscale, just like full-colour images, they’ll be printed in CMYK.

Find out more about Standard vs Rich Black for Greyscale Printing here.

 

Warm vs Cool Colours

The positioning of each colour on the colour wheel means it can be split into two categories: warm and cool. Colours can ‘speak’ to us on a visceral level, and their characteristics impact our visual perception. Colours like Red, Orange and Yellow are considered warm colours and have the longest wavelengths in the spectrum. Green, Blue and Violet are considered cool colours and have short wavelengths. Warm colours appear to advance towards our eyes while cool colours recede. It’s thought that this is why we associate warm colours as bold while their cooler counterparts are softer on the eye.

 

Additional Colour Theory Terms
What’s the difference between hues, shades, tints and tones? Let’s start with hue. A hue simply means colour. Therefore, tints, shades and tones are variations of a hue. A tint is where white lightens a hue (e.g. Red + White = Pink), and a shade is where Black darkens a hue (e.g. Red + Black = Burgundy). And finally, a tone is where Black, White or Grey is added to a hue to change the attributes that make up a colour, such as intensity or lightness.

 

Colour Theory does more than make prints look good. It’s a strategy that triggers emotion and helps make all kinds of printed material interesting and accessible. And for more news and inspiration, check out the array of posts on Mixam's Blog and visit our Support section for helpful guidance and advice on all things print.

Image Credit: Freepik and PicMonkey