Monday Morning Art School: how to read a paint tube

Knowing how to buy colors will save your time and money in the long run.

Pigments for sale on market stall, 2005, by Dan Brady. Thank heavens we don’t have to buy pigments in this form in America. It’s dangerous and inconsistent.

Modern painters expect to open a new tube of paint and squeeze out something recognizable. A tube of ultramarine blue made by any reputable manufacturer will have approximately the same amount of oil, and dry in about the same time to about the same gloss and transparency. The differences in binder and pigment load are subtle compared to the products available before the twentieth century.
That’s not by accident. Paint manufacturers subscribe to voluntary associations of quality control. One of these is Colour Index International (CII), a database dating back to 1925. It contains over 27,000 individual products sold under 13,000 different product names. This standard classification system ignores historic, proprietary, and generic names and gives you ‘just the facts, ma’am.’
Just as Benjamin Moore uses names like “Yukon Sky” to peddle grey paint, art paints are often marketed with evocative names. These names appeal to our sense of tradition, even when the old paint has no relationship to its namesake. For example, Indian Yellow no longer has anything to do with the urine of cattle which were fed mango leaves. Today it is made from lightfast diarylide yellow (PY83). If you buy Naples Yellow thinking you’re buying an historic pigment, think again: the modern paint is a convenience mix replacing the historic lead antimonate, which would do you and your painting no good.
The basic information on a tube of acrylic paint. If you’re not seeing this on the tube or display, proceed with caution.
Expect to find, at minimum, the following information on the label of your paint tube:
  • Manufacturer’s name or common name for the color.
  • The CII number and, sometimes, the name of the pigment(s).
  • The manufacturer’s lightfastness or permanence rating.

The CII code consists of two letters and some numbers. Most paints start with a “P” which means it’s a pigment, not a dye. The next letter is the color family:  PR is red, PY is yellow, etc. The number is the specific pigment included in the tube.
Save this link somewhere accessible from your phone: https://www.handprint.com/HP/WCL/waterfs.html
You’ll need it when you shop. This is Bruce MacEvoy’s Handprint pigment guide. It was built for watercolors but is generally true across all media. (Watercolor is the canary in the coalmine of pigments). All painters should understand lightfastness, transparency, and color shift. Granulation, bloom and diffusion, however, are watercolor-specific issues. 
Handprint doesn’t rate pigments for toxicity but comments on it in the notes. Most modern pigments are safe for the painters. For the manufacturers (who may be children in a third-world country) it’s another story.
Beautiful tube, evocative name, but it’s just a blend of PB 29 and PV 19 (Ultramarine Blue and Quinacridone Rose) which you already have on your palette. Many manufacturers offer the same mix under different names.
When you find two colors from different manufacturers that look the same, check their CIIs. Chances are that they contain radically different pigments.
A “hue,” is made of a blend of less-expensive pigments. 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.
Most manufacturers include their own lightfastness ratings on the tube. This is a measure of how fast the color fades. If it’s not listed, look it up.
The series number tells you the price. Why are some paints more expensive than others? That’s based on the raw pigments and what they cost the maker. Are pricier pigments better? Not by a long shot. Twentieth-century manufacturing gave us a new world of inexpensive pigments, which tend to be less toxic, higher in chroma and lightfast.
It’s about time for you to consider your summer workshop plans. Join me on the American Eagle, at Acadia National Park, at Rye Art Center, or at Genesee Valley this summer.

The problem with supply lists

I should KonMari my paint collection, not add to it. We go to workshops weighed down with too much stuff.

No, I don’t need any more watercolor pigments.
Many years ago, I took a workshop from a figure painter who specified cadmium green. I came home with an unopened tube and dropped it in a drawer. It’s still unopened.
I have great sympathy for students faced with a new supply list. In some instances, buying from them is redundant. For example, my list calls for Prussian blue, but if you already have phthalo blue, you’ve already got an excellent pigment for that color space.
It helps to understand the instructor’s reasoning. My list is based on paired primaries because I believe it allows the greatest range in color space. It occasionally changes as my painting technique evolves.  
Students usually show up with too much stuff because they don’t want to be caught without something they need. Most of what they carry, they never use. I’m feeling that urge to over-pack as I assemble the materials for Poppy Balser’s workshop in May.  Poppy, like me, is loath to send her students on spending sprees. However, it makes no sense to drive that distance and not be prepared.
And I don’t need a new mixing tray, either.
I trotted out my watercolor basket expecting to have to fill in color gaps. Actually, I should KonMarimy paints. What’s in the picture, above, is probably a quarter of the tubes in my basket. Does anyone really need five tubes of ‘opera pink’? More importantly, what is ‘opera pink,’ anyway?
Manufacturers love labeling convenience mixes with historic names. Consider Naples Yellow, used from the 18th to the 20th century. The real pigment is toxic lead antimonate. Modern paints labeled “Naples yellow” are made with a mix of modern pigments. You can make your own easily enough with white and yellow ochre.
That is the only name that really matters.
Pigments are listed on the tubes of all major paint makers in the form of Colour Index (CI) numbers. These are in tiny lettering on the side of most paint tubes. If the first letter is a “P,” that’s a pigment; if it’s an “N,” that’s a lake of a naturally-occurring substance like cochineal. The second letter tells you the general color family. The third tells you the actual pigment used.
A glance at my tube of ‘opera pink’ tells me it’s really PR122+BV10. The first is my old friend quinacridone magenta. Unfortunately, the second is a dye, rhodamine B, which bleeds and isn’t lightfast at all. I should pitch all five of those tubes.
My brushes, on the other hand, need help. New Yorkers will recognize some as being from the cheap bin at Pearl Paint.
If there is more than one CI number on the tube, you’re actually buying a hue or convenience mix. Many paint manufacturers sell hues of expensive pigments like the cadmiums and cerulean blue. They’re not consistent across brands, and they never have the handling characteristics of the more expensive paints they’re meant to imitate.
As with opera pink, even if the main pigment is lightfast, its partner may not be. Almost always, using single-pigment paint gives you the most flexibility in mixing.
There are many pigment guides on the web. Here is my favorite. Although it’s meant for watercolor, pigments are consistent across all media.