Cooperative Agreement Leads to Field Tests on Lasers for the Removal of Grafitti at John Day Fossil Beds National Monument
By Meg Abraham, J. Claire Dean and Jim Hammett, and Mark Gilberg
For several years NCPTT has sponsored research through a cooperative agreement with the Los Angeles County Museum of Art (LACMA) into the use of lasers as a tool for art conservation.
Among a number of directed projects, the conservation scientists at LACMA and NCPTT have been investigating the possibility of using lasers to remove graffiti from monuments and rock art sites. Protecting cultural resources against vandalism, looting and terrorism is among NCPTT’s recently-established research priorities. Because of their great value to scientists and cultural importance to Native American communities, rock art sites provide a significant opportunity to conduct laser cleaning tests.
Staff at John Day Fossil Beds National Monument (JODA) in Oregon initiated tests by hosting a field trial of a portable laser system for cleaning graffiti off of local basalt. Though primarily established for its paleontological resources, the monument also includes numerous archeological sites—both along the John Day River and in its uplands.
U.S. 26, a major federal highway between the east and west sides of Oregon, runs right through the gorge. While the highway allows visitors a convenient opportunity for monument visitors to see pictographs, it also makes the pictographs vulnerable to vandals, as demonstrated in last year, when vandals spraypainted their names in the vicinity of one of the most accessible pictograph panels in the gorge.
Under the supervision of J. Claire Dean, an archaeological and ethnographic conservator specializing in rock art sites, the trial use of the laser is designed to both demonstrate the feasibility of transporting and running it at a remote site and to study the results of the use of the laser in removing graffiti. The test area was located within Picture Gorge and involved the graffiti from 2002. While the test was not performed directly on the vandalized rock art panel but on an area of graffiti adjacent, it is hoped that this test will allow the Park Service, and the conservators and paleontologists involved to assess the usefulness of the technique for those applications.
The use of traditional solvents and other conservation chemicals in the field—specifically in the context of rock art—presents a number of problems, ranging from safety and contamination issues to disturbance of traditional practices. by means of deposited organic remains, solvents also may make it impossible to carbon date the rock art, fossils and other geologically interesting features of the site. Lasers can be used to remove much of the graffiti without the application of solvents.
The potential use of laser technology addresses many of these issues as it involves the use of light to treat a surface – a clean alternative to the use of chemicals, and one that is more likely to be culturally appropriate and acceptable to Native American communities.
Although the laser unit and power generator used in the JODA field experimentation would be difficult to transport into truly remote locations, it would not be impossible.
Recently, the authors have had the opportunity to present the history of technology and demonstrate the laser to the cultural committee and elders of the Confederated Salish and Kootenai Tribes of the Flathead Reservation. As in the treatment at Fossil Monument, graffiti was removed from rock in areas which are similar to rock art sights but are not known to have any rock art present.
Laser holds great promise as an on-site treatment method for rock art conservation. The conservators, tribal members and park staff continue to monitor the test to determine how the long-term consequences of this treatment compare with those of traditional solvent applications.