Located just beyond the violet band of visible light, ultraviolet (UV) radiation causes materials to fluoresce and phosphoresce depending on their properties. Invisible to the naked eye, ultraviolet radiation has a shorter wavelength than visible radiation. When examining a painting, UV can be used to determine surface anomalies. Varnishes, for example, fluoresce differently depending on their composition and age. Aged natural resin varnishes appear greenish yellow while newer synthetic varnishes may appear milky white to purple. The varnish on The Old Guitarist appears greenish yellow in UV, suggesting it is an aged natural resin varnish.
In detail 1 of the lower left corner of the painting, we see the greenish yellow fluorescence of the varnish. In places where the varnish is thinner the color appears blue or in some cases blue-purple. In detail 2, along the left edge of the painting, we see an area from which the varnish has been removed in a cleaning test. Once again we see the difference between the fluorescence of the paint and varnish.
2 days 19 hours ago The Art Institute of Chicago Congratulations to the Smithsonian National Museum of African American History and Culture on their grand opening this weekend. The building, designed by architect David Adjaye, is a truly historic addition to the National Mall in Washington D.C. #APeoplesJourney #MakingHistory
2 days 22 hours ago The Art Institute of Chicago Time machines, superheroes, wild creatures, and more… JourneyMaker makes every visit to the museum an adventure.
Try this new digital interactive for families in the museum’s Ryan Learning Center, located in the Modern Wing, or print out a tour at home.
3 days 20 hours ago The Art Institute of Chicago Today marks the autumn equinox and the official end of summer. Celebrate the changing of the seasons with the latest in ARTicle’s Sound and Vision series, matching songs from around the world with our encyclopedic collection.