From a very young age, we have been taught that red and blue make purple, just as yellow and blue mix to make green, and red and yellow make orange. However, how many times have you mixed a red and blue and the result is not purple or it is a yucky purple? You discovered that red and blue don’t make purple.
During my years of teaching color, I often hear painters complain about the difficulty in mixing a nice, clean and bright purple. They then go out and purchase tubes of purple paint and still they are not completely satisfied. It’s frustrating.
As a creative who loves the color purple, I overcame this frustration many years ago when I learned about the color bias that nearly every primary tube of paint carries. In other words, I taught myself to see the additional color or ‘color bias’ that primary tubes of paint carry. The definition and explanation of color bias is reviewed in my blog: Stop Using Warm & Cool Colors!
Red and blue DO make purple. The key is using a tube of red and a tube of blue that will produce that hue of purple you are wanting to use in your painting.
Typical tubes of red are: permanent rose, magenta, thalo red, cadmium red, cadmium red light, alizarin crimson hue, quinacridone magenta, naphthol red medium, pyrrole crimson, scarlet, pyrrole, red, vermillion, etc. (This is not an exhaustive list.)
Typical tubes of blue are: phthalo blue (red and green shades), cerulean blue, cobalt blue, Prussian blue, ultramarine blue, permanent blue, Antwerp blue, turquoise, manganese, etc. (This is not an exhaustive list.)
That is a lot of tubes of red and blue no matter which medium you are working in. …And the paint manufacturers keep creating more for us!
Note: In acrylics, watercolor and oils, the names of red and blue tubes may vary. However the variety of reds and blues is vast in each medium.
Which red and blue from the above makes a lovely purple? It can be overwhelming trying to choose. (Each swatch of color in the above chart is from different tubes of paint representing several brands.)
Red and Blue Don’t Make Purple …Why?
Why? Because artists try to use tubes of red and blue that contain yellow! We know that yellow is the color complement of purple and when they are mixed they de-saturate each other. In other words, when you mix a little yellow with purple it becomes dull or looses its saturation. The color chart below shows the mixtures that result from mixing various yellows and purples. You can see how the combination creates either a brown or gray/black.
The other factor that makes mixing purple difficult, is that many painters use a standard or typical palette of colors that does not allow them to make purple. Many color palettes are made up of the following colors: cadmium red, alizarin crimson, cadmium yellow medium (or new gamboge or Indian yellow), hansa yellow light (or cadmium pale or lemon yellow) and ultramarine blue, cobalt blue and curelean blue. Then they add optional earth colors along with white (acrylics and oil painters) and black (or neutral tint) to fill out your color palette of paint.
Red and blue don’t make purple with a color palette such as the one outlined above. To mix a clean purple, you must have a tube of red that carries a strong color bias of blue and does NOT carry any yellow. For example, the cadmium reds carry a color bias of yellow. Hence they will never mix a bright purple no matter which blue you use. Here I have mixed cadmium red with ultramarine blue. The result is a purple-black or gray.
Alizarin crimson, a popular color, carries a color bias of blue but it is a dull or de-saturated red. You can achieve a mixture that is somewhat purple using alizarin crimson, but it will never be a clean and bright purple. This is one of the reasons I do not like alizarin (permanent or otherwise) as explained in my blog: Could You Toss Your Alizarin Crimson?
You can see from the color mixture and swatch below, that alizarin and ultramarine do not make a bright purple. I added a little white at the bottom of the swatch so that you can see that it does make a grey-purple.
When I was working in watercolors, my secret to mixing purple was having permanent rose on my palette. I like that color for many other reasons. Hence, it was my favorite blue-red. Currently my blue-red tubes of paint, no matter my medium, are: permanent rose, quinacridone magenta or primary magenta. Below I mixed permanent rose and ultramarine blue to get a nice purple.
As you have been reading this article, you have noticed that the blue I am using is ultramarine blue. Why? Because it is a blue that has a color bias of red. There is no yellow or green in it. For fun, try mixing a cadmium red with phthalo or Prussian blue and see what happens. It certainly won’t be a purple because each of those blues and the red have yellow in them. Once again, red and blue don’t make purple.
Now for a bit of a twist. If you are up for experimenting, try your permanent rose (your nice clean blue-red) with one of your green-blues, such as cerulean blue and see what happens. I have provided an example below. 
How do you like this purple? It’s slightly grey but it still carries a purple hue. There is a little bit of white added at the bottom of the swatch. I encourage you to create a chart playing with your reds and blues.
Let me know which red and blue mixtures you have experimented with and which you prefer. Enjoy the discovery process!
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thanks it helps me a lot. I enjoy reading your post. Great job. thanks again, dema c
Thank you! I seldom use a purple yellow scheme because I did not like the colors when mixed. My next still life will have purple in it.
You are quite welcome. Thanks for checking in on my blog.