Plaster, stucco and wall paintings at archaeological sites are a rich source of information for archaeologists, as well as for researchers engaged in the study of such areas as building technologies and materials, artistic materials and paint, and history of art. For visitors, these remains have historical and artistic value that illustrates the past. Excavating exposes the remains to the effects of the climate after a period of many years during which they were buried in the ground in stable conditions. The “excavation shock”, that is to say, the rapid drying, contraction and expansion that are brought about by fluctuations in humidity and temperature, in addition to sun radiation , causes immediate destructive and weathering processes. The exposure, conservation and study of these sensitive elements are a complex challenge that requires cooperation between archaeologists, conservators and other experts. This is needed in order to manage the excavation and treatment at the site in accordance with the archaeological research goals and the conservation requirements, and includes testing for salts, identifying weathering patterns and the study of materials and of conservation methods of wall paintings.
The guide for excavating plaster, stucco and wall painting elements is intended to show archaeologists and conservators how to plan proper treatment for sensitive finds in an archaeological excavation, immediately upon the initial identification of the artifact, its exposure and conservation. It aims to provide a common language for archaeologists and conservators so as to prevent instances in which plaster, stucco and wall painting elements were destroyed or lost. They were destroyed due to inappropriate excavation methods, insufficient documentation, improper collection and transfer from the site to the laboratory or lack of suitable protection for the elements that remained in situ.