If anyone else had seen the painting The Colosseum Seen from the Southeast (c. 1700), by Dutch landscape artist Gaspar van Wittel (also known as Gaspar Vanvitelli), when it first arrived at the Harvard Art Museums, one might think the artist was capturing a view of the Roman Colosseum bathed in late afternoon sunlight, with its overall yellowish tones. However, the trained eyes of paintings conservator Teri Hensick recognized this effect as the combination of a discolored varnish with surface grime, not the original intent of the artist.

Hensick removed the gray surface grime with hand-rolled cotton swabs dipped in a solution of water and a chelator, an additive that makes water more efficient at dissolving dirt. Then she removed the dammar varnish, composed of natural resin, using swabs dipped in isopropanol-based solutions. She also removed old blanched retouchings. With each sweep of the swab, Hensick revealed an intense blue sky and the rich creams of the travertine stone. Once the painting was completely cleaned, she applied a new and more stable varnish, which further saturated the artist’s colors.

In fall 2014, visitors can look forward to seeing this revitalized Vanvitelli on view in the new galleries of the Harvard Art Museums. In the meantime, see the transformation of this stunning landscape in photos above.