What's That Stuff?: Pigments and Tempera Paint; The History and Chemistry Behind Pigments and Tempera Paints

Painters have used different types of mediums for centuries. There is oil, watercolor, acrylic, and tempera paint. One thing each of these paints have in common is the fact that each of their colors come from pigments. Pigments are usually minerals that are ground up and mixed with different binders to create paint. One medium whose popularity has risen and fallen through the ages is tempera paint. Created with pigment and a mixture of egg and water or casein (protein from milk) tempera paint has been a convenient medium used by artists for years.

Pigments are the properties in paint that give them their color. Pigments are various elements. These elements absorb and give off light, which humans then perceive as a number of colors. Different elements give off different colors. For example, the pigment “Cobalt green” is created when one gram of cobalt(II) chloride and five grams of zinc(II) oxide are mixed together and heated. The pigment that is then created gives off a dark green color. Pigments for paint are found it a ground substance very similar to thick sand. Not only made in sand form, during the Renaissance era pigments were dug out of the ground and shaped into chalk. In recent years, pigments have begun to be artificially created. One thing most people do not know is that pigments have different toxicity levels. The pigment “Emerald green” is very rare. It was created in 1808 as a replacement for Scheele’s green. This pigment was often used in paint as a color for houses but then found to be too toxic for use and was discontinued in the 1960s for causing deaths.

Tempera paint has been used for centuries starting in the Paleolithic ages. At that time they came from natural sources and were mixed with spit or fat from animals to create paint that was then used to paint caves. Later, in the twelfth century a monk used casein tempera paint. Casein paint has a casein binder. Casein is protein from milk. This was used for sometime then it’s popularity fell. Then, in the fourteenth century egg tempera was the primary medium for Italian artists. Many colors that were used are not in use today. One example of this is the color ‘Azurite’. It was one of the most prominent colors in artwork of the Middle Ages and during the Renaissance but was replaced when the color ‘Prussian blue’ was discovered. In the sixteenth century the popularity of egg tempera died down. In the late ninetieth and twentieth centuries artists began to study works of art and, wanting the same feel and look, began to use egg tempera again.

Binders are the item used in paint to make it stick to a canvas. The reason that this works is because most binders are something called a polymer. Binders can be many things including the protein from milk, fat, oil, or egg. Recently, there was a study conducted in which scientists created egg tempera paint the same as they did during the Renaissance era. They found that when applied to a canvas of some sort, these paints have certain properties (like the presence of lipids, proteins, and carbohydrates), which helped the paint stick to the canvas better. One example of how well an egg can work as a binder is simply found from doing dishes. Have you ever tried to wash your plate after having an egg for breakfast and find that it is a bit difficult to wash off? This is because egg sticks well and dries fast making it an ideal binder for paint.

When comparing tempera paint to oil paint one can see the differences very quickly. While oil paint is thicker while egg tempera tends to be much thinner. Oil paint dries very slowly and tends to look a bit murkier because artists often would mix the paints together while they dried. Egg tempera is known for being very vibrant and having a luminescent quality. With egg tempera you have to apply multiple layers. The good thing about this, however, is the speed at which egg tempera dries making this process go relatively quickly.

Pigments have been used for centuries and not only are good for paint but also different mediums of art such as chalk. Also, they are made up of different elements. Tempera paint is a popular medium and is convenient to make and use. Binders are what helps the pigments stay to a canvas and what, essentially, makes paint paint. There are perks and flaws to both tempera paint and oil paint but both are good for different styles of painting. Overall, tempera paints are a good choice of medium and have been shown to be so throughout the ages.