Alchemy meets chemistry in new research

Photo credit: David Heald

A new research paper analyses the degradation of white paint on Jackson Pollock's 'Alchemy' using infrared spectroscopic imaging.

Jackson Pollock was one of the greatest figures in the abstract expressionist movement of the 20th century. During his short life, he produced numerous masterpieces using his unique technique of poured painting. He routinely used a traditional oil paint (zinc oxide in linseed oil), but was unaware that this presented a potential threat to the conservation of his paintings. That is why researchers from Imperial College London and CNR-ISTM National Research Council, Institute of Molecular Science and Technologies (Italy) teamed up with the Peggy Guggenheim Collection in Venice, Italy to try and determine the degradation of specific painting materials on one of Jackson Pollock’s early pieces, 'Alchemy'.

Professor Sergei Kazarian and PhD student Alessandra Vichi used a non-destructive method to analyse several microscopic samples from 'Alchemy' containing zinc oxide, which was used as a common white pigment in the 20^th century. In the study, published in Analytical Chemistry earlier this year, they used micro-attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopic imaging to determine the damage resulting from the interaction of zinc oxide with fatty acids present in the oil binder of the painting. Even though there is little visible surface alteration, the researchers found that inside the painting, zinc soaps were growing freely not only throughout the painting stratigraphy, but in particular around a jellifying agent (aluminium stearate hydroxide) added in the paint formulation. This confirmed the hypothesis that the jellifying agent can accelerate the formation of zinc soap.

The technique, which has only been used on a handful of occasions to investigate multi-layered paintings, was successfully applied on samples of Jackson Pollock’s 'Alchemy' and helped detecting the detrimental formation of zinc soaps occurring inside the painting, thus resulting in its degradation. ATR-FTIR imaging technology has the potential to assess the chemical degradation in irreplaceable modern paintings and help the conservation work to preserve masterpieces for the future. 

References:

F. Gabrieli, F. Rosi , A. Vichi, L. Cartechini, L. Pensabene Buemi, S. G. Kazarian, C. Miliani. 2017. Revealing the Nature and Distribution of Metal Carboxylates in Jackson Pollock’s Alchemy (1947) by Micro-Attenuated Total Reflection FT-IR Spectroscopic Imaging. Analytical Chemistry. Analytical Chemistry (2017) 89, 1283-1289. (doi)

Jackson Pollock (1912–1956), 'Alchemy', 1947, oil, aluminum, alkyd enamel paint with sand, pebbles, fibers and broken wooden sticks on canvas. Peggy Guggenheim Collection, Venice.

[Article written by Dora Olah an Undergraduate student in the Department of Chemical Engineering.]