Amazing Facts
Laser Cleaning Research
The idea of using lasers to clean objects of material culture has fascinated conservators for 20 years. Although the potential has been quite clear, past efforts to apply the technology have been hampered by technical limitations, serviceability, and the cost of laser systems. Despite these problems, one practical application was established early and has since become broadly recognized: the use of short-pulse (Q-switched) neodymium: yttrium aluminum garnet (Nd:YAG) lasers to clean the marble of statuary and the exterior of heritage buildings.
Advances in laser system design have steadily broadened the potential for cleaning to include organic and other inorganic substrates. Nd:YAG's are available that offer a selection of output wavelengths, including the second and third harmonics at 532 nm (green) and 355 nm (near UV) respectively, along with the standard near-infrared output at 1064 nm. Choice of wavelength, as well as energy density and pulse duration and frequency, provides the flexibility needed to establish suitable emission parameters to clean museum objects safely.
CCI has recently obtained access to a new Nd:YAG with these capabilities through a collaboration with the National Center for Preservation Technology and Training (NCPTT), United States National Park Service, Los Angeles County Museum of Art (LACMA), and Getty Conservation Institute (GCI). Initiated and funded by the NCPTT, the collaboration combines the analytical capabilities of CCI and GCI with LACMA's new laser facility in order to advance the development of Nd:YAG ablative laser cleaning. CCI is also strengthening links with the National Research Council of Canada to enhance the analytical capabilities of the collaboration.
CCI will examine the surface effects of laser-induced thermal
and photomechanical action on selected cellulosic and proteinaceous
materials, stone, and corroded metals. The aim is to establish
the range of appropriate emission parameters for cleaning
these materials without damage, and to compare the efficacy
of laser cleaning and the resulting surface appearance with
those of other cleaning techniques.
