The Secret of Single Pigment Colors


The Secret of Single Pigment Colors

Q:  I visited your website and have read your article “Light Matters” and am impressed by your work and what you have to say about single pigments and having a large number of individual colors to work with.  Your idea of not mixing the colors, but rather buying individual single pigment colors, seems so contrary to what other painters suggest or do, that I am fascinated by your approach.  There is a simple, straight-forward logic behind what you say about the depth of colors coming straight out of the tube compared to those that one can mix by using two or three other colors.  Your ideas really hit home with me.

However, I have run into a serious snag in trying to follow your process of using single pigment paints.  I have been able to find only a few single pigment acrylic colors… cad yellow lemon (light), cad orange, cobalt, dioxazine purple, phthalo blue, and not many more.  I have always mixed colors, so painting without mixing the colors will be quite a new undertaking for me!  I’m thinking that if I want to complete a painting without mixing colors, I would have to have say…15-20 single pigment colors?  Or am I wrong about that? You said that you have a LOT of paints, so I suppose you meant that you have a lot of single pigment paints?  Is there a list of pure pigment colors that can be purchased and where to buy them?  I have tried to look at various sites and going through the colors one by one to see what they are made of, but it is time-consuming and I feel I simply am not going to find very many single pigment colors.  Is there somewhere a list of single pigment colors (landscapes being my main interest) that I would need?

A:  It is interesting to note that for hundreds of years artists used a palette of between 12 and 18 colors until the Industrial Revolution in the 19 century when that number doubled making the Impressionist movement far more impressive with the introduction of brilliant colors like the Cadmiums.  We are in the middle of the next revolution now with new colors being added almost every year.  The last time I did a survey there were close to 100 single pigment colors on the market, more for oils than acrylics. 

 Most manufacturers produce color charts for the range of colors that they offer.  You can look at these on their websites or in the art supply stores.  I do have one that I give out during my workshops that has over 25 single pigment colors on it, see below.  Manufacturers typically offer a selection of colors of which around 25% or more are mixtures of two or more pigments.  A quick glance at a color chart of a well known manufacturer of acrylic paints shows 85 colors of which around 70 are single pigment.  If you go to any manufacturer’s site, check the color charts at art stores, or just read the tubes, you will be able to discern for yourself which ones are composed of more than one pigment.   Perhaps the quickest reference technique is to look for the ‘color index’ right on the tube, that is the letter/number assigned to each color, for example PY35 is Cadmium Yellow Medium.  If a color has more than one color index, it is not a single pigment color.  A color named Cadmium Red Hue it is not a single pigment color and will have more than one index assigned to it, perhaps:  PR5 (Napthol Red) and PR207 (Quinacridone Red) for example. 

 Also, beware of colors that are not named after the pigment used to create them.  Hooker’s Green, Payne’s Grey, and so on.  Sap Green is not a single pigment color and the example shown below is a mixture of 4 different pigments: Phthalocyanine Green (PG36); Carbon Black (Pbk7); Transparent Red Oxide (PR101), and; Nickel Azo Yellow (PY150).  You can make the color yourself by mixing those pigments together, or as I would prefer to do, layer them in transparent glazes and/or veils to create a comparable color effect that I think is much more vibrant and interesting.  By making your own version of the color you have more control by altering techniques used to apply them, or simply by adjusting the amounts of each color.  In the example below, the color on the left is the manufacturer’s Sap Green, on the right is a combination of the 4 single pigment colors used to make Sap Green applied in transparent layers (glazes):











Cadmium colors also create some confusion for painters because they come in 3 different shades, light, medium, and dark, and they are all single pigment colors, not mixtures of two or more pigments.  You cannot mix Cad Yellow Medium with white (left below) and get a color effect that looks like Cad Yellow light (right below).  















Mixing colors is fine.  Just be aware that any mixture of two or more pigments will create a duller less luminous and vibrant effect than would be achieved by using a one single pigment color.   I do have a lot of paints because I don’t like to mix colors, but also because different paint manufacturers get their pigments from different sources so the same color from several companies can have very different hues and properties, esp. the natural organic colors like the browns.  Look at the difference between these two manufacturer’s Burnt Sienna colors.  One is more opaque and cooler, the other warmer and more transparent.  There is nothing you could mix with one of them that would give you the same color effect created by the other without the mixture looking much more dull and muddy.















Here are the same manufacturer’s versions of Burnt Umbers:














Also, contrary to what most painters are told, I use black, all three blacks: Ivory or Bone; Carbon, and Mars.   Each has its own unique properties and no mixture of various colors will ever yield blacks that are as cool, transparent, and intense as pure black pigment.  

I understand that not all painters have the desire or resources to own as many paints as some of us so for a well rounded palette I recommend an assortment of single pigments colors that includes at least one opaque and one transparent in each hue.  That way you will have a selection that Rembrandt would be envious of and with which you can create almost any effect imaginable:

 Essential Pigments

 Transparent/Semi-Trans (ST)         Opaque/Semi-Opaque (SO)

Ivory Black                                             Mars Black

Zinc White (ST)                                     Titanium White

Burnt Umber                                          Raw Umber (SO)

Burnt Sienna                                          Raw Sienna (SO)

Transparent Red Oxide                       Red Oxide

Transparent Yellow Oxide                  Yellow Oxide (Ochre)

Nickel Azo Yellow                                 Cad Yellow (Light, Med, Dark)

Quinadridone Red                               Cad Red (Light, Med, Dark)

Dioxazine Purple (cool)                      Quinacridone Magenta (warm)

Phthalo Blue (Green/Red Shade)     Cerulean Blue

Antraquinone Blue                              Cobalt Blue

Ultramarine Blue

Phtahlo Green (Yellow/Blue Shade)   Chromium Oxide Green

Pyrrol Orange (ST)                             Cadmium Orange




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