Painting the Town Napthol Red
In 1980, Robert Gamblin began to mix oil paint in a single-car garage. A graduate of University of Oregon with additional work at the San Francisco Art Institute, he had decided to pursue a life “as closely connected to painting as possible,” which in his case, meant creating the colors that would enable the work of fellow artists.
He spent that first year making only white paint as he taught himself the business and mastered the tools necessary for paint production. Thirty-three years later, Gamblin Artist’s Oil Colors produces some of the highest quality oil paints in the world. But how does his company manage to produce just the right shade of alizarin crimson, or achieve the ideal texture for manganese violet? The answer relies as much on science as it does on artistic sensibility.
It Starts with a Pigment
As much as we think artists are the ones with the colorful temperaments, every oil paint also has its own unique identity. Some are opaque, others are transparent. Some dry with a matte finish, while others maintain a high gloss. They dry at varying rates, have different textures, and handle differently when mixed with other colors.
“From a painter’s perspective, there’s a great value in having colors that have different personalities,” said Scott Gellatly, product manager at Gamblin. “There’s more visual interest, and a heightened painting experience when you have a great diversity of characteristics in your colorant.”
But what is it that gives these paints their different personalities? The answer largely comes down to pigment. Today, there are generally two broad categories of paint pigments: inorganic and organic. The former class contains the historic, ore-based pigments that were once made by grinding certain minerals or earth with mortar and pestle. For instance, burnt sienna was derived from the earth found around Siena, Italy, while ultramarine blue was once ground from the semiprecious (and more than semi-expensive) lapis lazuli.
Since the early 1900s, however, synthetic organic pigments have also become available. These pigments are derived from organic chemical compounds, and have greatly expanded palette possibilities and generally made paint more affordable.
“Every one of those powders has a very different source and makes a slightly different kind of paste,” said Robert Gamblin. “We’re maximizing the feel of the paint so that it has the spiritual resonance that I feel is contained within every pigment.”
Although these pigments might look similar to the naked eye, their differences become apparent when viewed under a microscope. As might be expected from something derived from crushed rock, the particles found in mineral pigments are larger, heavier, and more irregular than their synthetic counterparts, which are smaller, more uniform, and contain fewer impurities.
Because light can’t easily pass through the dense particles of mineral pigments, these paints are highly valued for their opacity. Using titanium white as an example, Gellatly noted that opaque pigments “tend to reflect the light right off the surface of the paint back to the viewer’s eye, so we get this very dense, saturated appearance of color.” More modern colors however, tend to be more transparent, making them ideal for tinting and glazing.
Although high in saturation, mineral colors also tend to be more muted, as their chromatic value isn’t as pure. With their irregularities, mineral colors such as cadmium red will show the reflectance of other wavelengths besides red when viewed on a spectral curve. A modern organic however, such as napthol red, will almost exclusively reflect light that appears as red, making these colors bolder and more intense. They retain this intensity when mixed with other colors, while mineral paints tend to “gray down,” as Gellatly called it.
“How this feeds artistic intention is if you’re a painter that wants to create the effects of colors of the natural world or the effects of natural light,” said Gellatly, “then those mineral colors might be well-suited to you. They give the artist a naturalistic color mixing potential. Whereas the modern organics are really great for painters that want a more expressive use of color with a much greater intensity.”
Putting the Oil in Oil Paint
Of course, oil paint isn’t just made up of pigment. It also contains—wait for it—oil. Most oil paints, Gamblin colors included, are made using linseed oil, which is derived from flax seeds. Modern colors, with their smaller pigment particles, generally require more oil since there is more surface area to coat. This leads to paint that is smoother, glossier, and takes longer to dry.
Actually, oil paints do not technically dry at all—they oxidize. Unlike watercolors, which literally dry through evaporation, oil intakes oxygen, which initiates the polymerization process, which is when molecules link up into chains. Gellatly likened this to a room full of people mixing and mingling. If everyone joined hands with one another, then eventually, individuals would no longer have the freedom of movement to pace the room. This is essentially what happens to oil molecules as they oxidize. By linking up, these molecules become fixed in place, locking in the pigment and forming the rigid layer that we think of as “dry.” The more oil involved, the longer this process takes, which is why paint with a high oil content can stay wet for a week or more.
Since oil paint hardens by exposure to oxygen, the top layers of an oil painting generally dry more quickly than the lower layers. This can lead to cracking however, since it means the lower layers must expand and become rigid beneath an already inflexible top layer. To prevent this, many painters employ the “fat over lean” rule. By using paints with a high oil, or fat, content over paints with less oil, the layers presumably will dry at roughly the same rate.
Getting It Right
Of course, knowing the scientific rationale behind what makes an oil paint behave a certain way is only half the battle. When developing new colors, Gamblin and his team will test recipes in their lab in order to get as close as possible to a desired color, while bringing out the best qualities of each pigment. “We’re essentially working in the volume of one tube at a time and measuring in hundredths of a gram of the pigments,” said Gamblin. But then comes the real test: gauging how the paint performs on canvas. “A lot of the time involved in developing a color is essentially working with it in the studio, and then going back and tweaking it, and working with it in the studio again,” said Gamblin. “The studio is really an extension of the lab.”
The studio, after all, is the only place to truly determine whether pigment and oil have come together in a way that can capture the beauty and feeling of an artist’s vision. Which is, at its essence, what creating artists’ colors is all about. More than the mechanics of gloss, opacity, or dry time, Gamblin notes that creating oil paint is about something deeper. “What we’re really doing,” said Gamblin, “is we’re concentrating emotions trapped in oil and pigment and putting them in tubes.”