Sunday, April 11, 2010

Extreme mould and water damage

The Studio was approached in mid 2009 to conserve two artworks that were water damaged whilst being shipped in a cargo container. Both artworks were rolled up at the time of being exposed to water and remained exposed for an extended period of time. The end result was two stained, creased and mould damaged artworks. The artworks are on a medium to heavy weight, coated, calendared, wove, white, machine made european paper and are ink drawing (most likely felt tip pen).

Before Images

The first treatment carried out was surface cleaning with a soft brush to remove any loose mould. Further surface cleaning with a rubber chemical sponge was done to remove ingrained dirt. The artworks were then subjected to solubility testing before any further treatment began in order to determine if the ink would react negatively to aqueous treatments. The testing was carried out with water (pH7), IMS (industrial methylated spirits) and calcium hydroxide (pH10). No lateral or horizontal movement of the media was observed, it was therefore considered safe to perform aqueous treatments.
The objects were immersion washed in 50/50 solution of IMS and water. The alcohol bath was utilised to kill any active mould. Further washing was carried out in pH7 water in order to remove any soluble acids and discolouration. In subsequent washes the pH of the water was increased to pH8 – 8.5 with calcium hydroxide to help remove insoluble discolouration and neutralise insoluble acids.
Once washing had removed as much discolouration as possible, the overall discolouration was bleached by spraying with a 1% solution of hydrogen peroxide (pH9). Once the overall bleaching was complete, bleach was applied locally to the more tenacious mould stains with a fine paint brush. After each bleaching session the object was humidified and washed in pH8-8.5 water.

Washing after bleaching helps remove any discolouration that has become mobile during bleaching. Washing in an alkali helps neutralise any acids that might have developed during bleaching. Washing in an alkali also places an alkali reserve in the paper which will neutralise any acids that might develop in the future. An alkali environment discourages existing and future mould growth.
After washing and bleaching the conservator performed several tear repairs with Japanese paper and starch paste and minor retouching of areas of lost media. Finallt the artworks were humidified one last time before pressing to remove the cockling. The artworks were pressed for nearly two weeks before being delivered to the client.

After Images