Ask the Expert

People celebrate paintings as aesthetic achievements and for the profound messages they often convey, but I also like to appreciate them as works of engineering. Art history has unfolded not only by means of cultural shifts, but also because of available technology. Chemical engineering and materials science have a real influence on the finest and most revered expressions of human creativity. That’s an important message in a class that I teach in the Spring called “Art, Chemistry, and Madness: The Science of Art Materials,” with my wife Sara, who is an artist.

A painter in late medieval times would have to work very differently than a painter could today. He would paint not on a canvas but on a heavy wood panel. Of course he would not use acrylics, or even oils, but instead he’d apply tempera paint likely made from egg yolks. He could not paint a scene while actually being there. He’d be forced by the lacking portability of his paints and their containers to work entirely in a studio, perhaps by torch light. Finally, his palette of pigments would be much more limited than it is today.

The Renaissance brought not only a revolution in thought, but also a couple of sweeping technical transitions for artists. One was in the invention of oil-based paints. The advantage oils had over temperas is that the oils dried much more slowly. This property gave artists new abilities, such as novel ways to blend and texture colors. Few did this better than Jan Van Eyck, whose Arnolfini Marriage (at left) is a masterpiece of early oil technique.

Van Eyck painted the Arnolfinis on wood. Today we expect fine paintings to be on  canvas, but only later in the Renaissance did artists begin to paint on fabrics. Wood panels offered sturdy surfaces but they were prone to warping. Wood panels were also burdensome to transport. Canvas, by contrast, was light and could be rolled up. Canvas and paint, however, can degrade with variations in heat and humidity. It’s an engineering issue for modern museums to ensure a consistent environment to preserve early canvasses (the study of the specific ways that the paint on differently constructed paintings will crack is a fascinating area called “craqueleur”).

Over the next few centuries, the palette of pigments expanded considerably. Blues have always been fairly rare in nature, and therefore in the palette. Throughout the Renaissance, painters were obliged to paint the robes of the Virgin Mary with an “ultramarine” paint made from precious lapis lazuli, which was worth its weight in gold. In the early 1700s, however, German paint makers finally succeeded in producing one of the first synthetic paints: Prussian Blue. Other synthetic paints, including a synthetic ultramarine, followed, expanding the palette and reducing its cost beyond what nature itself could allow.

The real burst of synthetic pigments occurred as a consequence not of demand from artists, but because of the industrial revolution. Mass production of textiles required mass availability of cheap new dyes that eventually found their way into paints. The development of a popular purple, aniline-derived dye called “Mauvine” by William Henry Perkin set off a wave of industrial dye-making and innovation.

In the late 1800s the impressionist masters began working with these pigments extensively. They were aided, as well, by another innovation. Leaden paint tubes with caps. This may seem trivial, but these paint containers allowed them to take paints out of the studio and into the field where their subjects were. For example, Monet could go to his pond and paint water lilies (an example is at left). He could capture light and colors exactly as they saw them, instead of recreating them indoors  and entirely from memory.

In the 1950s, artists gained access to a new paint chemistry: acrylics. Jackson Pollack, Andy Warhol and Roy Lichtenstein used them. Acrylics are highly texturable, come in a wide variety of colors, and dry quickly – allowing for quick work – but they don’t last all that long. Aniline-derived pigments also can change color over time. A question regarding many modern paintings, therefore, is their longevity.

Most people don’t walk into San Francisco’s deYoung Museum or Madrid’s Museo del Prado thinking about colloid chemistry (pigment particles suspended in a dye) or interfacial adhesion (paint sticking to primer), but the works they see are products of these phenomena. Understanding how artists have been equipped over the centuries provides a more complete insight into the development of our collective artistic legacy.