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.