When CCI was approached to treat a silkscreen on linen that had a large water stain, it was seen as an opportunity to explore stain removal techniques in the context of paintings on unprimed fabric supports. Conservation treatment techniques in this area were not well established nor had they been highly successful, and better treatment options were definitely needed. The project was truly a collaborative effort in which the expertise and skills of conservators, conservation scientists, and conservation interns specializing in the treatment and research of paintings, textiles, and paper were brought together.

The Legend of Red Lake Ontario (#8/50) by Josh Kakegamic is a large (2.63 by 1.155 m) seven-colour silkscreen print on a loosely woven linen fabric. The print was in relatively good condition except for the unsightly tide lines that had resulted from a ceiling leak. Water-soluble components in the fabric had leached from the centre of the affected area (leaving this area lighter in colour) and been redeposited in a dark tide line at the wet/dry interface.

The first step in the treatment was to develop a procedure that would reduce the dark tide line to a degree that would render the silkscreen 'exhibitable'. The procedure was based on local suction treatment. Initial testing was undertaken with a suction disc that had been designed by Stefan Michalski (a conservation scientist who is Manager of CCI's Preventive Conservation Services). This disc provided suction pressure that was high enough to move liquids through fabrics without forming new tide lines, and was fitted with a fibre-optic light to help align the stain over the small work area. Although initial testing with this device was successful, the disc's small area was not appropriate for treating such a large stain. A MuseuM Services Corporation Suction Table (often used by textile conservators) would be more suitable for treating large areas, but it produced a lower suction pressure than the disc. However, due to the characteristics of the linen support (loosely woven and sized), the lower pressure was sufficient to reduce the stain without creating new tide lines. Treatment was therefore carried out with this suction table.

Conventional solvents were tested on the stain, but had no effect. Based on her paper bleaching research, conservation scientist Season Tse suggested trying sodium borohydride — a mild-to- moderate-strength reducing bleach that does not degrade cellulose. This proved to be successful in decolourizing the darkest part of the tide line. The bleach was applied by brush and, while under suction, an airbrush filled with deionized water was used to rinse residual bleach, decolourized products, and some diffuse staining from the fabric. In areas where further bleaching was required, fine control was achieved by applying a 'mist' of the bleach with an ultrasonic mister, a technique that had been refined by textile conservator Jan Vuori in a concurrent project involving stain removal on Oceanie, la Mer, a silkscreen by Henri Matisse.

Detail of stained area before treatment.

Detail of stained area after treatment.

Applying the rinse with an airbrush.

Reweaving the tear, right side completed.

The treatment was completed with the assistance of two conservation interns, Geneviève Saulnier and Agata Sochon. Geneviève carefully used the capillary action of small damp blotters, combined with suction and an airbrush rinse, to reduce further the small areas of the tide line that remained visually disturbing. She also repaired several small tears along the tacking margin using a reweaving technique that was essentially invisible from the front surface.

Even with the tide lines taken care of, the areas of canvas that had become lighter in colour due to the water damage remained quite noticeable. To deal with this problem, the lighter areas were inpainted. Inpainting is a technique in which colour is applied to areas of paint loss to re-integrate the image; it is a common technique in treating paintings but is seldom considered in treating textiles. Before proceeding with this procedure, tests were undertaken by Agata to determine whether or not a pigment applied to the exposed canvas could be removed using suction techniques, should removal be necessary in the future. The tests proved that such inpainting would be 'reversible'. Geneviève then prepared a diluted 'stock' colour using tube watercolours and applied it to the surface of the warp threads in dots or thin lines. Capillary movement along the thread dispersed and unified the colour. Just enough colour was applied to integrate the overall tone of the fabric support.

Once inpainting was completed, a new stretcher was constructed for the silkscreen to replace the missing auxiliary support. The new stretcher was sealed with Marvelseal (a polyethylene/aluminum/nylon laminate) to prevent acids in the wood from migrating into the artwork, and then a heat-set, non-impregnated sailcloth was stretched over it to act as a taut overall support for the silkscreen. The artwork was hand-stretched over this sailcloth and stapled with rust-proof staples to the reverse side of the stretcher. Finally, a protective backing board was attached to the reverse of the stretcher and a travel frame was constructed to provide protection during travel, handling, and storage.

This object crossed the boundaries of several traditional conservation disciplines, and its treatment required a collaborative and innovative approach. At CCI, where conservators of different specialty areas and conservation scientists work in close proximity, this type of inter-mingling of creative ideas, diverse knowledge, and experience can produce new and more effective treatment techniques.

Further information on this and related treatments can be found in the following articles:

Daly Hartin, D., S. Tse, and J. Vuori. "A Collaborative Treatment: Reducing Water Stains on a Silkscreen on Linen." pp. 293–298 in ICOM Committee for Conservation 12th Triennial Meeting Lyon 29 August – 3 September 1999: Preprints Volume 1. London, UK: James & James (Science Publishers) Ltd., 1999.

Vuori, J., D. Daly Hartin, S. Tse, A. Maheux, and A. Ruggles. "Local Stain Removal from "Oceanie, la mer" by Henri Matisse: The Development of a Reducing Bleach Technique using a Suction Disk, Ultrasonic Mister, and Airbrush." pp. 164–175 in Conservation Combinations: Preprints of a Conference (North American Textile Conservation Conference 2000). Asheville, NC: Biltmore Company, 2000.