Colour Theory for Interior Design - How to Use a Colour Wheel to Choose Colours

Summary: Find out how colour theory is used in interior design, how a colour wheel works, how colours can set a mood and how to choose colours. In this DIY guide we take a look at colour theory and find out all about primary colours, secondary colours, tertiary colours, neutral colours complementary colours and how colours can effect moods. Also find out about warm colours and cool colours and what the best way is to pick a colour or theme when redecorating a room.

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Whether you are decorating a room or buying accessories, it helps to know something about colours and how they work together.

Colour Wheel

Colour Wheel for use in picking colours for interior design

For centuries, artists have used the colour wheel to determine which colours go together and contrast against one another.

Primary Colours

Red, yellow and blue are the three primary colours on the colour wheel. These colours are placed at equal intervals on the wheel, and all other colours are made up from a combination of these colours. They are called primary colours because they cannot be created by combining other colours.

Primary colours:

  • Red
  • Yellow
  • Blue

Secondary Colours

Secondary colours are created when two primary colours are mixed together. Red and yellow make orange, red and blue make purple.

The secondary colours are placed on the colour wheel in between each primary colour. So if you look at the colour wheel diagram, you will see that between yellow and blue you have green. If you got yellow paint and blue paint and mixed equal amounts together, you would get green paint.

Secondary Colours:

  • Green (mixing yellow and blue together)
  • Purple (mixing blue and red together)
  • Orange (mixing red and yellow together)

Tertiary Colours

A tertiary colour is what you get when you mix a primary colour with the secondary colour next to it on the colour wheel. Tertiary colours are named by the colours used to create them, ie blue-green or yellow-green.

Colour Wheel

Tertiary colours - created by mixing primary and secondary colours together

Complementary Colours

If you pick two colours which lie directly opposite one another on the colour wheel, these are called complementary, or contrasting colours.

You would think that because they sit opposite each other, they wouldn’t go together, but actually they complement one another and can be used together to great effect. Be careful to use a complementary colour sparingly though, otherwise the two colours together can be overpowering.

  • Yellow-orange
  • Red-orange
  • Red-purple
  • Blue-purple
  • Blue-green
  • Yellow-green

Analgous Colours

A common trick in colour scheming is to pick one colour from the wheel, then use the colours on either side of it for accents.

For example if you pick blue for the main colour of a room, you might use hints of blue-green and blue-violet to add a bit of interest here and there to stop the main colour from saturating the room too much.

Tints and Shades

When you look at a paint chart, it’s not just made up of primary, secondary and tertiary colours of course. Many colours are made up of tints and shades of those main colours.

Tints are made by adding varying degrees of white to a colour to make it lighter – these make up the majority of the wall paint charts.

Shades are made by adding black to a colour to make it darker. Tints and shades are a good way to use a range of tones based on one colour scheme, and create a calm and harmonious feel in a room.

It is easy to use the colour stripe cards from DIY store colour mixing stations to pick out a colour and use it to choose a range of tints and shades that can be used throughout the room.

Neutral Colours

White, black and greys are completely neutral colours – or rather, a lack of colour. These can be used to great effect with any colour for a striking scheme.

  • Black
  • White
  • Grey
  • Can also include brown and beige

Colours and Moods

Colour can have a great effect on our moods – large corporations use them purposely to influence us without us realising it, for example sunny yellow is often used in hospitals now as it is a positive colour that encourages healing. Orange is sometimes used in restaurants as it increases appetite.

Red has long been known as the colour of passion, but toned down to a lighter pink it makes you think of romance – a good example of how tones and shades can be used to scale a mood up or down.

Blue is a very calming colour, and green is peaceful – it’s very close to nature and can be either stimulating, with a vivid bright grassy green, or quiet like a dark forest.

Purples are linked with spirit and creativity, but you do need to be careful to make sure they don’t look grey.

  • Yellow = Positive colour encouraging healing
  • Orange = Increases appetite
  • Red = Passion
  • Pink = Romance
  • Blue = Very calming effect
  • Green = Peaceful and very nature-like
  • Purple = Spirit and creativity
  • Tints and Shades = Used to help scale a mood up or down

Warm Colours

If you draw a line through the colour wheel from red-purple to yellow-green, you divide the wheel in half where the warm-cool divide is.

Reds, oranges and yellows are all warm colours. Warm colours will advance in a room, and if used in excess can make the room appear smaller.

If you have a very large room, painting it with very warm colours will make it seem cosier and less imposing, but if your room is small to start with be careful not to use too strong a warm colour for the walls.

Lighter tints will always dilute the advancing effect of a warm colour, while darker shades will enhance it.

  • Red
  • Orange
  • Yellow

Cool Colours

Purples, blues and greens are all cool colours, although they can be made warmer by using darker shades. Cool colours are receding, so you can use them to create an illusion of space in a room.

  • Purple
  • Blue
  • Green

Choosing Colours

If you are completely redecorating a room, try to start with a blank canvas. Move all non-essential items out of the room, and if it’s viable put a coat of white emulsion on the walls – if you are planning to change the colour of the walls this is a good idea anyway, as it will help dilute the colour that's underneath.

Once you have your blank room, you need to take into account the furniture you can’t or aren’t willing to get rid of.

If you have a collection of antique mahogany furniture you need to make sure you select a sympathetic colour scheme. However, don’t go and paint your room bright pink because it matches the sofa – you might want to consider having the sofa reupholstered if you’re after a complete change.

Consider swapping furniture, pictures and accessories from other rooms too.

Once you have a collection of items that are definitely going to live in the room, you can look at them and start to think about which colours will work well with them.

If a large photo or painting is a feature of the room, you might pick out a colour from it to use.

Once you have your main colour, use the colour wheel and the information above to choose a complementary or analogous colour, or tints and shades to help create your palette.

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