How to Mix Colours When Painting in Acrylics

Why I like to mix my own colours

There are hundreds of different paint colours to choose from when you visit the art store. If you are like me, they all look so inviting you want to buy them all. However, good quality paints are expensive so you probably don’t want to buy a separate tube for every colour you might want to use in your paintings. Learning to mix your own colours is not only going to save you a lot of money, it will give you a greater range of colours to choose from for your work. Read on to find out how I choose which colours to use for mixing.

Why you need more than one red, one yellow and one blue to mix the perfect colour

Some people will tell you that to mix any colour you only need only one red, yellow and blue because these are the primary colours.  Technically, this is true but that is not quite the way it works when it comes to painting.  Here’s why.

Artists’ paints, or any paint for that matter, are not true primary colours.  

Paint companies cannot replicate primary colours exactly.  Primary colours come from refraction of light, like the rainbow.  Instead, the paint companies use pigments to imitate primary colours as best they can but they always lean a little towards one or other of the other primary colours. You will notice that artists’ paints usually come in a number of different hues for each primary colour.  These are commonly referred to as warm and cool hues.  If you have a warm and cool hue of each of the primary colours you will be able to mix any colour you like. You will also need some white to adjust the tone of your colours and I think it is worth adding at least one green to your painting kit.

The paint companies then decide to give these different hues fancy names which can make it even more difficult to know exactly what you are getting.   In the next section I will explain a bit about warm and cool hues and why they make a difference when it comes to mixing your own paint colours.

Warm and Cool Colours

The way I like to think of warm and cool colours is that warm colours are like the sun.  They are reds, oranges and yellows.  Cool colours are like the ocean, greens and blues. 

When it comes to buying paints you will be confronted with a whole range of blues, yellows, reds and greens.  Each one of these colours can be categorised as warm or cool.  Ultramarine blue, for example, is considered a warm blue.  The reason for this is that although blue is a cool colour, Ultramarine contains a little bit of red in it which is a warm colour. 

On the other hand, Pthalo blue is considered a cool blue because it contains a little bit of green.  In the case of red, Alizarin Crimson is considered a cool red because it contains a little bit of blue and blue is a cool colour.  Burnt Sienna is a warm red because it contains a little bit of yellow, a warm colour.

This concept is simple enough to remember when you are using paint straight from the tube but things can get a little muddy when you start to mix your own colours.

It becomes a bit clearer when you take a look at the colour wheel.

The Colour Wheel

Here is a colour wheel chart I created.  You can download a copy to keep by clicking on the image.

Primary Colours

These are the three primary colours spaced evenly around the wheel.  They are:

• red (warm)
• yellow (warm)
• blue (cool)

Secondary colours

When you mix any one of these primary colours with any one of the others you create secondary colours which fit in between each primary colour:

• orange (red and yellow)
• green (yellow and blue)
• purple (red and blue)

Tertiary Colours

When you mix a secondary colour with one of the primary colours it already contains you create a tertiary colour.  These sit in between the secondary and primary colours on the colour wheel.  Examples of tertiary colours are:

• turquoise (blue and green) or [blue + (blue+yellow)]
• violet (purple and blue) or [blue + (blue and red)]
• lime green (green and yellow) or [yellow + (yellow+blue)]

A tertiary colour can also be described as a warm or cool version of its nearest primary colour.  For example, any hue between:

• yellow and orange is warm yellow
• orange and red is warm red
• red and purple is cool red
• purple and blue is warm blue
• blue and green is cool blue
• green and yellow is cool yellow

Complementary colours

Complementary colours are those that are opposites on the colour wheel.  When you mix a a secondary colour with its complementary, i.e. one of the primary colours it does NOT contain, you create a neutral colour.  The result of mixing complementary colours together will be:

• black
• brown
• grey

Understanding warm, cool and complementary colours is going to help you when choosing which colours to use for mixing.  Here’s why.

Choosing the right colours for mixing

Suppose you want to make green, for example.  You mix yellow and blue, right?  Yes, but you have a range of blues and yellows to choose from so how do you know which ones to use?

That depends on the type of green you want to make.  For an olive green you might use a warm yellow like yellow ochre and a warm blue such as ultramarine.  Both these colours contain some red.  Therefore, when you use a warm yellow and a warm blue to make green there will also be a little bit of red in the mix. 

Red is the complementary colour to green because they are opposites on the colour wheel.  When you mix red and green together you get brown. Consequently, when you mix a warm yellow and a warm blue you will end up with a brownish (or warm) green like olive.

So let’s look at cool colours.   If you use a cool yellow and a cool blue to mix green it will be a more bluish green, such as you might see in the ocean. A green that is closer to blue than yellow is a cool green.

When you use a cool blue with a warm yellow, or vice versa, you can get another whole range of different greens in between the warm and the cool.  Therefore, if you have blue and yellow paints in both warm and cool hues you can make virtually any green you want.

You can save time in working out exactly how to get any colour you want by making yourself a chart like this.

List all your paint colours along the top and then again down the side of the chart.  Start with the first colour in the top row of your chart.  Mix a little bit of that colour with each of the colours on the left hand side of your chart and paint a little swatch where they intersect in the table.  Do the same with each of the colours on the top row until you have completed the grid.  You now have a reference chart for every colour you can mix with your paints.  This should save you some time and frustration when you are looking to find exactly the right colour for your artworks.

Mixing grey, brown or black

Now suppose you want to make grey, brown or black.

As previously mentioned, neutral colours like grey and brown are made by mixing all three primary colours together, or mixing one colour with its complementary.  That is you mix yellow with purple, blue with orange or red with green.  You will achieve all sorts of different greys and browns depending on which complementary colours you mix together but there are usually fairly equal amounts of each colour in the mix.  You can also make black by mixing complementary colours together but it does make a difference which paint colours you use.

Many of the paints you buy already contain quite a bit of white in them.  Some examples are Naples Yellow or Cerulean Blue.  It is also worth mentioning that the amount of white added will differ between brands of paint also.  When making black it is important to use paints that have little or no white in them.  Many paint colours have white added to aid in opacity.  Burnt sienna and Ultramarine Blue, or Pthalo Green and Napthol Crimson are two of my favourite combinations for mixing black.  Again, there is a fairly even mix of the two colours.

There are lots of different ways to make black but it will always lean slightly towards one or the other of the primary colours.  That’s why black paint from a tube is not always the best black to use in your paintings.  The black you should choose will depend on the other colours in your painting. 

Mixing shadow colours

When you mix complementary colours together and there is more of one colour than the other you end up with a toned down version of the dominant colour.  This toned down version of a colour is what you should use when applying shadows to your paintings.  For example, if you were painting a red apple sitting on a yellow table with light coming in from a window, you would mix a little green into the red colour of the apple and use this for the shaded side of the object.  In order to paint the shadow that is cast onto the table by the apple, you would mix a little purple into the yellow you used for the table.

The way to tone down a colour is to add a little bit of its complementary.  The amount of complementary colour you add will depend on how strong you want the shadow to be.  That will depend on the strength of the light source, or the tonal range of the painting.  For darker shadows, you would add a bit more of the complementary colour.  

For shadows on white objects, the same rules can apply because when painting sunlit areas of white objects, the colour will not be true white but will lean towards one colour or another.  Note:  I never use white paint to show white objects.  Instead I use a very pale version of whichever colour gives the best contrast to the surrounding area.  More often than not, the shadow colour I use for white objects will be blue or purple.

Shadow colour chart

Here is another little exercise you can do work out all the different shadow colours, browns and greys you can make.

Start by painting a swatch of each of the three primary colours across the top of your page, red, yellow and blue.  At the bottom of the page paint a swatch of each secondary colour, green, purple and orange.  Each secondary colour should be directly beneath its complementary primary colour. 

Next you can start again at the top with any of the primary colours, say red, and mix in a little bit of green.  Paint a swatch of the mixed colour directly beneath the red at the top.  Then add a little bit more green to the mix and paint another swatch beneath that one. 

Repeat this process until you reach about half way down the page.  At this point you want the two colours to be roughly a 50/50 mix.  Then you can work your way up from the bottom of the page, starting with the green, adding a little bit of red each time you move up the page. 

Repeat this process with the blue and the yellow and you now have a chart with all the different shadow colours, greys and browns that you can make yourself.

Key points to remember about mixing colours

Remember that warm colours are like the sun and cool colours are like the ocean.  

I recommend you have at least one warm and cool hue of each primary colours in your painting kit

Knowing whether your colours have a a warm or cool hue is going to help you to decide which colours to use for mixing

A colour wheel chart can be useful for identifying primary, secondary, tertiary and complementary colours

Complementary colours mixed together will tone down any colour so you can create browns, greys, blacks or any shadow colour.

As always in art, there are going to be situations where these rules don’t apply. One example is if there is reflected light in your painting.  However, the methods I have outlined above for identifying and mixing your own colours are a great place to start.  Hopefully, my suggestions will save you a bit of time and money.  You don’t need to buy endless tubes of paint of different colours when you know how to mix your own.

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