RESEARCH

improved chelating agents for the cleaning of iron and copper stains from art and architectural stone (In collaboration with Ms. Martha Singer of the  Museum of Modern Art in New York City)

Removal of metallic stains from stone is a challenge for architectural and art conservators because the available solutions force them into a compromise.  Usually, stains are removed by applying poultices containing chelating agents that are not specific to the stain and/or are too acidic for basic substrates.  As a result, when removing stains, conservators chelate the substrate itself or etch it, rendering it more vulnerable to deterioration.

 The purpose of this study is to investigate the usefulness of highly specific chelating agents from the medical field for stain removal in conservation.  Specifically, we will compare the effectiveness of chelating agents used to treat heavy metal poisoning (Desferal and d-Penicillamine) to that of chelating agents commonly used in conservation (di-sodium EDTA 2 , thioglycolic acid, ammonium citrate, DTPA 3 ) in removing iron and copper stains from limestone and marble.

These projects will lead to an improved awareness of the limitations and perils of current cleaning methods in the conservation community.  More importantly, the exciting results obtained in our preliminary experiments suggest that the proposed work will lead to major improvements in conservation methods via the introduction of highly specific chelating agents for stain removal from stone.  In addition, we will develop a systematic methodology for the evaluation of new, improved agents.  Indeed, the approach introduced in this proposal can be transferred to other conservation specialties such as outdoor sculpture, paper, textiles and paintings.  

This project is funded by the National Center for Preservation Technology and Training, a division of the U.S. National Parks Service, and administered through the San Francisco Museum of Modern Art.