Color theory is a fundamental part of mixing colors and learning how to paint in oils and goes way beyond simply understanding that mixing red and yellow makes orange. You also need to understand the relationship between colors.

By learning about color in more depth, you will avoid all sorts of common problems, such as mixing muddy colors, an oversaturated painting or a painting that looks flat.

Oil Color Painting Terms, Explained

Hue and Pigment

These are simply alternative words to ‘color’

Color Temperature

Simply refers to a color being either warm or cool. However, this is compared to the colors around it. For example, red on it’s own would be warm, and blue on its own would be cool. However, yellow would be a cool colour if you lay it next to the red, but a warm colour if you lay it next to the blue. And, if you lay a warm blue against a cool red, the red may appear cooler than the blue.

There are warm or cool shades of each color. For example, Cadmium Yellow Light,

Is considered to be a cool yellow, as it leans towards green, whereas Cadmium Yellow deep, is a warm yellow as it leans towards orange.

The easiest way to understand this is by looking at a color wheel.

Value and Tone of a Color

This is simply how light or dark a color is. As a simple example, Ultramarine Blue is obviously much darker in tonal value than Lemon Yellow. However, the more similar the colors get to each other, the harder it can be to get the correct value. In this case, comparing your colors to a grayscale chart can be a considerable help.

In any case, value should always be considered before color.

Intensity/Saturation of a Color

This is how pure or bright a color is.

Transparency and Opacity

This refers to how transparent or opaque a color is. For example, if you lay a transparent blue over a yellow, the yellow will show through to some degree, depending on the level of transparency of the blue. As a result, the new color will be a shade of green. If you lay an opaque color over the top, then the color beneath will not show through. This is why transparent colors are used for glazes.

Complimentary Colors

Complimentary colors are the colors opposite each other on the color wheel. For example, the complimentary color to red, is green. The complementary color to blue is orange and the complimentary color to yellow is violet.

Harmonious Colors

Harmonious colours sit beside each other on the color wheel.

How to Darken a Color when you’re Oil painting

To darken a color, you might immediately reach for the black, however this is not the best way as it will also significantly dull your color intensity. The best way to darken a color, is either to mix it with a darker version of the same hue, or add a touch of its complimentary color. The latter is also a great way to tone down an intense color and make it appear more natural.

How to Lighten a Color

Using white to lighten your colors, can make them appear chalky and flat. You might first try adding the same color, but a lighter version of it. So for example to lighten a Cadmium Yellow Deep, you could try adding a touch of Cadmium Yellow light. However when lightening a color in this way, keep in mind that this may also alter the color temperature.

Mixing Colors to Make Black

You might wonder why you should learn how to mix black in oils, when you can just go to the art store and buy a tube of ready-made black. Personally, I have never owned a tube of black paint! I find that black straight from a tube is very flat. I prefer to mix my own blacks and this can be done in many different ways, depending on the temperature you are aiming for.

Here are a few colours that make a nice black

• Ultramarine Blue/Burnt Sienna
• Ultramarine Blue/Transparent Red Oxide/Alizarin Crimson
• Ultramarine Blue/Cadmium Red
• Equal amounts of blue red and yellow

If you would prefer to use a black from a tube, then try adding another pigment to adjust the temperature and add depth.

I would encourage you to experiment. Black, doesn’t necessarily mean devoid of colour or temperature. It simply means the darkest value you can achieve. Make it interesting!

Basic Oil Paint Color Palette

My own basic oil painting color palette consists of a warm and cool, transparent and opaque version of each primary, along with a couple of earth colors and a white.

Here is a basic palette you can use to start with, but this will evolve over time as you experiment with alternatives:

• Cadmium Red – Opaque/Warm
• Alizarin Crimson – Transparent/Cool
• Ultramarine Blue – Transparent/Warm
• Cerulean Blue – Opaque/Cool
• Cadmium Yellow Light – Opaque/Cool
• Indian Yellow – Transparent/Warm
• Raw Umber – Semi-transparent/Cool
• Raw Sienna – Semi-Transparent/Warm
• Titanium White

How to Avoid Mixing Muddy Colors

• Try not to use more than three colors in your mix
• Avoid using black straight from a tube to darken a color
• Avoid adding white to lighten a color. Use a lighter value of the same color instead
• Use transparent colors in your mix where possible, as transparent colors are less likely to make mud
• Avoid over blending
• Clean your paint brush regularly between areas

How to Mix Flesh Color in Oils

There is no, ‘one color fits all’ because of course this varies hugely from one person to the other. This is why using a ‘flesh color’ direct from the tube would be a mistake. Generally, any color named ‘flesh’ is unlikely to match anyone’s skin tone.

That said, there is nothing wrong with using flesh color as part of a base mix. You can then add other colors to the mix, to get the color you need.

As an example, if you were to mix ‘Flesh’ with Raw Umber as a base colour, you can then add the following colors in varying amounts to get the temperature and tone you are aiming for:

• Alizarin Crimson
• Yellow Ochre
• Ultramarine Blue
• White

However, there is no need to invest in a ‘Flesh’ color at all. You can get a variety of flesh colors just by mixing three primaries and white. Here is a good example:

• Yellow Ochre
• Ultramarine Blue
• Cadmium Red Light
• Titanium White

For darker skin, you might use Alizarin Crimson instead of Cadmium Red and also Burnt Umber.

Whatever the skin tone, temperature matters. So experiment!

How to Mix Brown in Oils

A whole variety of browns can be achieved by mixing the three primaries. You can then add a little white to make them lighter.

However, I must say, I do really like the earth colors that come in a tube, such as Raw Umber, Burnt Umber, Burnt Sienna… You can then adjust them by adding other pigments in varying amounts.

Mixing Colors to make Greys for Oil Painting

You can mix a huge variety of greys by mixing two complementary colors with varying amounts of white. As an example, by mixing blue and orange and adding the mix to white in varying amounts, you will achieve some interesting greys.

Mixing Colors to Make Purple

Mixing a vibrant purple is not as simple as mixing blue and red together!

Since yellow is the opposite color to purple, it is very important that the red and blue you choose to mix your purple do not contain any yellow pigment, otherwise your purple will be much less vibrant. Your red, will need to lean towards blue, in order to make a clean and intense color. A good example would be Permanent Rose, which leans towards blue. By mixing Permanant Rose with Ultramarine blue, you will get a lovely, clean purple.

This should be considered when you are mixing any secondary color. That said, of course, sometimes you may want to create a less intense color, but it’s important to understand how to reach the desired intensity.

Mixing Colors to Make Orange

As discussed above, you must choose the right red and yellow to arrive at a clean, bright orange with a good intensity. So, in this case, the opposite colour to orange, is blue. You need to choose a yellow and a red, which don’t contain any blue pigment, otherwise, again, your orange will be dull.

For an intense, warm orange, mix a warm red and a warm yellow. A cool yellow and a cool orange (ie leaning towards blue) will result in a duller, less intense orange.

How to Mix Green in Oils

Again, you need to bear in mind all of the above. So, if you want a bright, intense green, you must not choose a blue or yellow that contains any red pigment, as red is the opposite color to green.

That said, we often do want to tone down our greens to create more naturally occurring greens, particularly for landscapes. Green direct from a tube can be very acidic and unnatural. Try instead, either adding a touch of red directly to your green, to make it more natural looking, or better still, try mixing your own. Here are some example mixes to try:

• Cadmium Yellow Light/Burnt Umber
• Cadmium Yellow Light/Ultramarine Blue
• Cadmium Yellow Light/Pthalo Blue

How to Mix Lime Green in Oils

Sometimes we actually want to mix an acidic green, for instance when painting fruit. A good example mix would be:

• Sap Green, cadmium Yellow and Ultramarine Blue. You can then ‘glaze’ with lemon yellow to alter the depth and hue once it’s dry.

How to mix Teal in Oils

• Lemon Yellow
• Cerulean Blue
• White

How to Mix the Color of Tropical Water in Oils

Again, this is just an example of what I consider a good starting point:

• Ultramarine Blue
• Pthalo Blue
• Cadmium Yellow Light
• White

You would then add more yellow where the water is shallow.

Again, experiment!

A Final Note about Color Mixing

Color theory is a complex subject, but whilst it’s important to understand the basics, by far the best way to learn, is to do. Experiment! Make notes of what works and what doesn’t. In time, color mixing will become instinctive.

Source: https://kickinthecreatives.com/mixing-colors-oil-painting/