This past May, I had the privilege to attend a course on stain removal with chelating agents at the Art Institute of Chicago’s Paper Conservation Laboratory. This course was a pivotal moment in my career, and will critically alter the way I approach stain removal in works of art on paper. Until recently, conservators have been limited to using oxidizing or reducing agents on tenacious stain complexes, which can be damaging to the cellulose.
Chelation agents open up a whole new world of possibility. They remove metals, which in many instances are the source of stains in paper. But they do not damage the cellulose, making them a much more desirable option for treatment over oxidizing & reducing agents. The word chelate derives from the Latin root chela, meaning bearing a claw. This claw describes the chelating agent’s molecule, which surrounds free metal ions like a claw, and carries them away.
Chelating agents have been used for many decades in Western medicine to treat heavy metal toxicity in human patients. Due to the potential connection between metal contaminants and foxing in paper, chelators such as EDTA were tested in the conservation setting. As it turns out, in many instances they can yield excellent treatment results. The staff and facilities at the Art Institute are top notch, and the course was incredibly informative. Antoinette Dwan, one of the course instructors, is a paper conservator in private practice. She has been using chelating agents for over a decade, and had many useful insights into the practical application of chelators in a paper conservation studio.
I am looking forward to continuing to integrate this knowledge base into my conservation practice.