New Exhibition Unfolds the “Bizarre” Stories Behind Centuries-Old Pigments

Cow urine is one of many strange ingredients included in the University of Manchester’s new show exploring the history and chemistry of artists’ palettes

In this 12th century illuminated manuscript Mary Magdalene announces the resurrection to the apostles. manuscript from the St. Albans Psalter, St Godehard's Church, Hildesheim

An artist searching for color in modern times has to do little other than select a tube of pigment off the shelf. But centuries ago, creating the perfect pigment involved getting creative with ingredients such as crushed insects, burnt bones or cow urine.

In a new exhibition at the John Rylands Library of the University of Manchester, U.K., the "bizarre stories behind artists' palettes" are on display along with a selection of centuries-old manuscripts from the collection. Visitors can ogle vivid yellows, deep blues and brilliant greens now through August 2018.

Several short videos from the library, posted to YouTube, tease the contents of the new exhibition.

In one, Carol Burrows, the Heritage Imaging Manager with the library, shines an ultraviolet light on a painting from a volume of Indian paintings crafted in Dehli during the 18th and 19th centuries. The painting shows a woman cloaked in a rich yellow dress. Under the UV light, that yellow dress pops out of the page, glowing fluorescent yellow.

Shining UV light on paintings is an effective, non-invasive way to get clues about the pigments the artist used. Some pigments, like this popular Indian yellow, made from cow's urine, offer a characteristic glow, Burrows explains. (To achieve the bright pigment, cows were "fed exclusively on mango leaves," according to the Museum of Fine Arts in Boston.)

The UV light can also reveal where people touched up paintings — later additions appear darker than original paint, according to Pigments through the Ages, an online exhibit from the nonprofit Institute for Dynamic Educational Advancement.

In other videos, experts from Manchester University and other institutions explain the differences between black ink and black paint used in manuscripts. They also go into how to identify different kinds of blue and the importance of the color purple.

Making pigments was a key part of creating illuminated manuscripts. Often, the process was complicated. One of the most prized pigments was the deep blue made with the semi-precious stone lapis lazuli, writes Allison Meier for Hyperallergic. A YouTube video from online shop Master Pigments explains that simply grinding the stone wasn't enough. A 14th-century recipe written by the Italian painter Cennino d'Andrea Cennini calls for powdered lapis lazuli, beeswax, gum rosin and gum mastic (both of the latter are resins from trees). The wax and resins must be melted and combined with the powdered stone. Then the mixture must be kneaded like dough before it dries for three days. The maker must then heat and knead the mixture again before pigment extraction.

Fra Angelico blue pigment extraction

The extraction step involves squeezing the dough in a bowl of water for hours, until pigment particles come out and fall to the bottom of the bowl. All impurities remain in the dough. Only then can the brilliant ultramarine that color skies and the Virgin Mary's dress in many European paintings be retrieved.

With such a laborious, arcane process, it's no wonder the Manchester University's exhibition is called "The Alchemy of Colour."

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