AIC's 42nd Annual Meeting

Pencil marks present a great challenge to removal when applied, purposefully or otherwise, to textiles such as unprimed cotton canvas. This problem is relevant to textile conservation as well as the conservation of contemporary paintings, where unprimed canvas is frequently left exposed, such as in the works of Morris Louis, Robert Goodnough, and Kenneth Noland. Errant, accidental marks and those applied intentionally as acts of vandalism are equally problematic. Pencils are generally comprised of low quality amorphous graphite, an electrically conductive semi-metal allotrope of carbon, pressed together with clay. When used to write, the powdered crystalline flakes of graphite break off; when this occurs on canvas, these powdery flakes become entrapped in the fiber and thread bundles, and are difficult to remove without compromising the structure of the fabric. Methods of safe removal were tested including laser ablation, mechanical removal methods, and reversed microemulsion cleaning agents including siloxane systems. The effectiveness of the method of removal was determined by visual results, the hand of the fabric, and microscopic examination to check for fiber damage and discoloration. Mechanical removal proved ineffective and impractical, and an appropriate microemulsion system could not be found that would not compromise both the aesthetic and the hand of the canvas. Successful results were only obtained with laser ablation at 532 nm; other wavelengths tested (266 nm, 355 nm, and 1064 nm) did not give satisfactory results. Ageing tests on the ablated canvas samples are forthcoming.