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Thursday, April 10, 2014

Sunset paintings are more than just art

If you wanted to study meteorological conditions before the advent of modern recording devices, what would you do? Well, if you’re like Christos Zerefos of the Academy of Athens or his colleagues, you’d look at old paintings. The researchers used paintings of sunsets made from the year 1500 to 2000 to estimate the amount of pollution in the air at those times.

First off, you may be wondering what could have produced enough pollution to blot the sky hundreds of years before the industrial revolution. The answer is volcanic eruption. Sure enough, paintings made within a few years of major eruptions have redder skies than paintings made at other times. This is because the ash and dust in the air after an eruption scatter the sunlight, shifting the ratio of red to green light.

To test how accurately a painting could be in predicting the clarity of the atmosphere, the researchers asked Panayiotis Tetsis, a colorist and landscape artist, to paint a series of sunset pictures from the island of Hydra. Unbeknownst to Tetsis, during the experiment there happened to be a Saharan dust storm blowing over Greece. You can see the results below:
Tetsis paintings
Greek landscape painter Panayiotis Tetsis created the top images on June 19 and 20, 2010, respectively. The photographs below them reflect the real sunsets on those evenings. There were more aerosols in the sky, and more red in Tetsis' painting, on June 19.
P. Tetsis (paintings) and C. Zerefos (photos).

The top two panels are of Tetsis’ paintings, the bottom panels are photographs taken while he was painting. The panels on the left were made during the dust storm, the panels on the right were made the next day. Notice how much redder the sky is during the dust storm in both the photographs and the paintings.

If earlier artists were equally good at capturing color differences, then paintings made hundreds of years ago could be useful for determining pollution levels.

Zerefos, C., Tetsis, P., Kazantzidis, A., Amiridis, V., Zerefos, S., Luterbacher, J., Eleftheratos, K., Gerasopoulos, E., Kazadzis, S., & Papayannis, A. (2013). Further evidence of important environmental information content in red-to-green ratios as depicted in paintings by great masters Atmospheric Chemistry and Physics Discussions, 13 (12), 33145-33176 DOI: 10.5194/acpd-13-33145-2013.