What Color is your Stick?
It’s sunset and you are reaching into your pastel box for that perfect shade of yellow ochre to paint the highlights onto the rugged cliffs in front of you. There it is, brilliant and warm in your palette. Did you ever wonder how that stick made its journey to your box? Where did the pigment originate and how was it made into a pastel? How have colors changed through the history of art and pastel making?
If you were lucky enough to hear Bob Strosahl’s talk at the annual meeting of the PSWC this month, you got an earful and an eyeful of information about pigments. Bob, a chemist by training, is the founder and president of Great American Artworks, and has been making pastels from formulas he developed himself for the last sixteen years. I called him up to learn more about pastel manufacturing and the colors we use to paint our world.
As most of you know, dry pastels are made from pure pigment and some sort of binder. Various binders and fillers are used throughout the industry, including gum tragacanth, gum arabic, clays, chalk, gypsum, and others. The ratios of binder to pigment affect the softness of the stick, and most pastel makers keep these formulas secret. Pastels first appear in history as an art media in the 1400s, and pastel pigments have changed with our developing knowledge of light, chemistry and new materials.
Pigments can be divided into those that come from nature and those created completely in the laboratory. The history of artists’ use of pigments is fascinating. Pigments have been used by humans to make art for hundreds of thousands of years, as observed from archeological sites in ancient African caves, and the cave paintings in France. Those pigments all came from nature; they were literally dug from a hole in the earth, crushed from charred bone, or concentrated from blood, ground plant or animal parts. Some of these ancient pigments are still in use today. Variations of the earth mineral iron oxide create the colors sienna, ochre and umber. This mineral ore (named for the places it was originally mined in Sienna and Umbria) is heated and changed to create different shades of color.
Other colors that were dangerous or difficult to acquire naturally have since been replaced with synthetic versions, thanks to modern chemistry. Beginning in the 6th century A.D., artists used very expensive ground lapis lazuli to get deep blues. Also known as ultramarine (meaning beyond the sea, since it was traded from far away) this color became associated with royalty because of its expense, and was later known as royal blue. It was a French man who developed the formula for creating the color synthetically and thus the term “French Ultramarine.”
The color carmine was originally produced from ground cochineal beetles imported from Central America. After the Spaniards conquered Mexico this colorant was imported to Europe and used by painters throughout the Middle Ages and into the 19th century. The process of deriving it is called “laking” and gives us the names crimson lake and carmine lake. As these colors proved to be fugitive, they were mostly replaced with alizarin crimson in the late 19th century.
Some pigments were highly toxic, such as Paris green, which contained copper arsenic. Often used as wallpaper pigment, this may have led to Napoleon’s demise in his prison on St. Helena.
Many artists including the Dutch masters used Indian Yellow, a popular color imported from India. The color was later said to be made from the urine of cows fed only on mango leaves, and thus was banned in Europe since this was considered inhumane. (Although this story may be urban legend.)
It is interesting to imagine Edgar Degas in his Paris atelier, grinding lapis lazuli or insect wings to make pastels. More likely he went down the street to his friend Gustav Sennelier, who ground these exotic materials to formulate pastel sticks to Degas’ specifications.
Despite their “colorful” history, most pigments are now made in the laboratory, from carbon compounds derived from petroleum. Pastel makers import large batches of pigment from the various color houses, striving to match color lots to bring the pastelist consistent color with each stick. Pigments are then mixed with liquid and binders and formed either by hand or machine into a stick, then dried. The result? Your gorgeous palette of pastels with just the right turquoise to paint the ocean, the rich red of the hibiscus against the ochre wall, and the deep orange of the setting sun.
With thanks to Bob Strosahl and Craig Lemley.
If you want to know more about the history of color in art, you might want to read Color: A Natural History of the Palette. By Victoria Finlay, (2003). Random House. ISBN 0-8129-7142-6 or A Perfect Red: Empire, Espionage, and the Quest for the Color of Desire, by Amy Butler Greenfield (2005). Harper Collins ISBN 0-06-052275-5
