Despite improvements in identifying organic materials in wall paintings, there remains much to understand about the nature and role of organic materials in these works. The knowledge of the different types of organic materials in wall paintings and of their behavior is fundamental for developing appropriate conservation and maintenance procedures. Not knowing the presence and the nature of the organic material contained in a paint layer can result in inappropriate interventions using harmful materials and can cause irreversible damage.

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The GCI is participating in a new scientific research initiative that addresses this issue. The Organic Materials in Wall Paintings project (OMWP) seeks to develop an analytical protocol for the study of organic materials used in wall paintings. The project brings together an international group of conservation science laboratories that will provide their expertise in the study of wall paintings and in the use and evaluation of analytical techniques.

This research will be made possible by studying over 60 wall painting replicas from the Tintori Center in Italy, established by the late conservator Leonetto Tintori in 1983. The center is a repository for hundreds of wall paintings replicas of known composition, simulating different techniques and material combinations and created for research purposes.

Replicas from the Tintori Center will be used to test various investigation techniques—from noninvasive in-situ examination (e.g., using UV light to see fluorescence) to more sophisticated analytical procedures that require sampling (e.g., gas chromatography). Each technique will be evaluated for its potential and limits in identifying organic materials. In addition to vetting these techniques, the project will produce a large set of catagorized data that will constitute a comprehensive reference for consultation and comparison when studying a wall painting.

The GCI's main role in this project is to coordinate the research by the different laboratories—including the GCI's—and to integrate the results into the development of an appropriate protocol for the characterization of organic materials. The GCI will also manage, disseminate, and make accessible to the larger conservation community the information produced by the project.

A feasibility study of the project began in 2002 and was completed in spring 2003. As part of the feasibility study, two samples were circulated to selected laboratories for noninvasive investigations, and microsamples were collected for invasive nondestructive and invasive destructive investigations. In June 2003, a project workshop was held in Italy, at which the project participants discussed the feasibility study and sought to define further the analytical protocol. This year the project will continue with an examination of 18 additional samples with over 40 types of wall painting techniques, including the use of egg, animal glue, oil, and gum as binders.

The application of the methodology to a case study—a project component in development—will help demonstrate the process and illustrate the level of information required to ensure the appropriate conservation of a painting. It is hoped that the project will result in more detailed study of wall paintings prior to intervention, reducing the risk of irreversible damage to wall paintings during intervention.