Category: hues

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Monday Morning Art School: some basic color theory

Mixing paints is simple if you understand how pigments work.

Fallow field, 12X16, oil on canvasboard, available.

In theory, you can paint with just four pigments: red, blue, yellow and white. For beginning painters this is sometimes a good idea, because it’s the fastest way to learn color management. It simplifies the thought process so you have only one decision to make at a time, and it is easier to get a more unified color scheme.

But there is a limiting factor, and that’s the impurity of pigments. They all have overtones that muddy them up in certain mixes. That’s why your local paint dealer uses many, many more pigments than just red, blue, and yellow.

Claude Monet’s palette shifted over time, but included these paints:

  • Chrome yellow
  • Cadmium yellow
  • Viridian green
  • Emerald green
  • French ultramarine
  • Cobalt blue
  • Madder red
  • Vermilion (red)
  • Flake white
  • Ivory black (before 1886)

These are sets of paired pigments. That means he has a warm and a cool of each color, plus black and white. 

I use paired primaries as well, omitting the green but adding in some other earths. (Here are my supply lists for oils,  acrylics, and watercolors.)

The distinction between warm and cool colors has been important in painting since the Impressionists. Warm colors are said to be hues from red through yellow and cool colors are said to be the hues from green through violet. Each hue around the color wheel also has a warm and a cool version.

There’s no factual hot or cold point because this is just a poetic description that works. Much of what we believe about the psychology of color is hocus-pocus, based on the teachings of 19th century cult leader Madame Blavatsky. However, it’s true that if the light is what we call “warm,” the shadows are what we call “cool,” and vice versa.

Paired primaries are simply warm and cool versions of each color.

When we say that lemon yellow is cooler than cadmium yellow deep, we mean that if you are trying to mix a greenish yellow, you’ll get a clearer shade with the lemon than you will with the cadmium yellow deep. The warm-cool language is just a convenient way of saying that.

Different pigments may look the same when squeezed out of the tube, but there the similarity ends. Pigments are impure, and you have to learn and work around those impurities.

To better understand color space, watch Gamblin’s excellent video on the subject, here.

Three blues that look similar out of the tube, but behave very differently. The ‘glaze’ on the left is the undertone. Courtesy Gamblin paints.

Mass tone is the color a pigment is straight out of the tube, dense and unmixed with another color. No real-world pigment, however, is as pure as a color on a video screen. While two pigments may look the same to the naked eye, their behavior when mixed can be radically different.

Undertone is the color revealed when a paint is spread thin enough that light bounces back up from the substrate. Some pigments are fairly consistent when moving from mass tone to undertone. Others have significant color shifts. Not understanding those undertones tones can lead to muddy mixes.

Ultramarine, Prussian and phthalo blue are colors that shift radically from mass tone to undertone. They’re all so dark out of the tube that their differences aren’t apparent to the naked eye. But dilute them, and you’ll find a wide range of blues.

Cadmium Red Hue is usually made with napthol red and a little white. They mix very differently, which is why the hue is a bad substitute for the real pigment. (In its own right, napthol is a fine red, however.) Courtesy Gamblin paints.

Undertones are why buying “hues” instead of pure pigments can be such bad value. Take, for example, cadmium red hue, which is usually a napthol red with a small amount of white added. Out of the tube, the two paints are indistinguishable, but they mix very differently.

To see a pigment’s mass tone, put a small dab of paint on a smooth white board or glass palette and draw it down with a knife, creating a uniform, solid stripe that completely obscures the painting surface.

To see the undertone, draw the sample down again so it is translucent. You should be able to see minute variations in the color, and in the covering power.

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Monday Morning Art School: don’t buy ‘hues’

The imperfection of paint is what gives it its liveliness and depth, but it also makes mixing colors tricky.
Autumn, by Carol L. Douglas. This painting contains no reds. The red tones are a combination of cadmium orange and quinacridone magenta.

A “hue,” is made a blend of less-expensive pigments that mimics more expensive ones. There is nothing inherently wrong with these pigments, but they don’t behave the same as the more expensive ones, and you should at least know what you’re buying.
Generally speaking, there’s little to be gained by buying a hue mimicking a more expensive pigment. If you are comfortable painting with a hue, then learn what’s in it and mix it yourself. You always have the greatest flexibility by working with pure pigments (rather than mixes) out of the tube.
How do you know if something is a hue, not a true pigment? First, ‘hue’ is often in the name, as in ‘cadmium yellow hue’. But you should learn to read the paint tubes, too. I’ve spelled that out in How to read a paint tube. It’s information every painter should know.
Three blues that look similar out of the tube, but behave very differently. The ‘glaze’ on the left is the undertone. Courtesy Gamblin paints
A mass tone is the color a pigment is straight out of the tube, dense and unmixed with another color. No real-world pigment is a pure color. While two pigments may look the same to the naked eye, their behavior when mixed can be radically different.
Undertone is the color revealed when a paint is spread thin enough that light bounces back up from the substrate. Some pigments are fairly consistent when moving from mass tone to undertone. Others have significant color shifts. This is where painting with hues can lead to muddy mixes, because they will not behave the same way as the original pigment.
Ultramarine, Prussian and phthalo blue are colors that shift radically from mass tone to undertone. They’re all so dark out of the tube that their differences aren’t apparent to the naked eye. But dilute them, and you’ll find a wide range of blues. Luckily, they’re all inexpensive pigments, so they’re never mimicked.
But they can be used to make hues of other colors—particularly phthalo, which is often found in viridian hue. Real viridian green (PG18) is a moderately staining, moderately dark and moderately dull blueish green. Viridian hue is terrifically staining and powerfully bright, because of its phthalo component.
Cadmium Red Hue is usually made with napthol red and a little white. They mix very differently, which is why the hue is a bad substitute for the real pigment. Courtesy Gamblin paints.
Cadmium red hue is usually a naphthol red with a small amount of white added. Out of the tube, the two paints are very similar, but they mix very differently. There’s nothing wrong with naphthol red; it’s my red of choice, but it doesn’t behave much like its cadmium cousin.
Even paints with the same pigments can have different undertones depending on the manufacturer. That comes back to the imperfectability of pigments and their essential complexity.
A drawdown test showing a paint’s undertone. Courtesy Utrecht paints.
If you’re considering two different pigments, or thinking about switching brands, you can test them. It’s fast and easy. To see their mass tone, put a small dab of paint on a smooth white board or glass palette and draw it down with a knife, creating a uniform, solid stripe that completely obscures the painting surface.
To see the undertone, draw the samples down again so they are translucent. You should be able to see minute variations in the color, and in the covering power.
This old paint chart from my childhood explains tints, shades and tones. It’s so old, it’s from before they banned black. 😉
But to understand the behavior of each more fully, you need to make tints, tones and shades of each sample.
  • A tint is a color plus white.
  • A shade is a color plus black.
  • A tone is a color plus black and white.
Even when the mass tone appears quite similar, two close colors will act very differently when mixed. Their unique qualities of tinting strength, chroma, undertone and color temperature come into play here. But mixing paint with white or black immediately adds another layer of complexity. Different blacks and whites have their own undertones. Titanium white is cool. Zinc white is warmer, but it’s also brittle and thin, making it a bad choice for general painting. Ivory black is slightly warm.