J. Cult. Heritage 1 (2000) S259–S262 © 2000 E ´ ditions scientifiques et me ´dicales Elsevier SAS. All rights reserved S1296-2074(00)00140-0/FLA Laser divestment for natural history museum collections John F. Asmus* University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0360, USA Abstract – A series of probative laser cleaning and divestment tests has been performed on a wide variety of the materials encountered in natural history museum collections. These tend to be quite different from the substances customarily encountered in fine art collections. Initial results are shown for laser cleaning of minerals, fossils, wood, ancient textiles, feathers, as well as mummified and frozen tissue. The preliminary results indicate that laser cleaning and divestment may have even more utility in the natural history field than in fine art conservation. © 2000 E ´ ditions scientifiques et me ´dicales Elsevier SAS Keywords: laser / museum / natural history / fossil / mineral / feather / wood / clean 1. Introduction For the past 27 years laser surface divestment in the conservation and preservation fields has focused on the surface divestment of fine arts objects in museums and architecture (viz. paintings and stone sculpture). The earliest laser tests in the laboratory and in the field were concerned with classical Italian Renaissance marble sculpture [1]. Subsequently, laser divestment techniques have been investigated for the conservation of other classes of art such as fresco and easel paintings as well as stained glass panels and drawings [2]. The great majority of the items comprising the world’s museum collections are not fine art pieces. They are items of historic significance that are housed in natural history museums. An enormous diversity of materials may be encountered in these institutions. Materials commonly found in such mu- seums include plant fibres and wood, animal and insect tissue, minerals, fossils, bones, animal and human mummies, leather, paper, and many other materials. It is the prognosis for the application of laser cleaning to this latter class of substances that is addressed in this investigation. 2. Historical background In October of 1973 some surplus laser components from various sources were assembled into a laser at the Laboratorio delle Pietre Dure in Florence. Profes- sor U. Baldini authorized its use in the conservation of a Donatello-school marble statue of a prophet from the Duomo. This trial began the 20-year saga that ultimately led to the acceptance of laser divest- ment as a stone conservation procedure. Figure 1 shows this first laser in operation in Florence. 3. Test specimen selection An inquiry to the president of the Society for the Preservation of Natural History Collections (SPNHC) elicited the following list of materials as those encountered in the conservation activities of this field: fossils, hair, minerals, pottery, bones, feathers, insects, wood, cloth, stone tools, leaves. A visit to the San Diego Natural History Museum produced some 50 specimens for laser test cleaning. Most, but not all, of the categories listed above were represented. * Correspondence and reprints: jfasmus@ucsd.edu