Soapstone Sculpture

The main issue that exists with this object was the transfer of a Tyvek impression onto the surface of the stone. This object had been previously treated in 2001 with harsh abrasives and re-waxing of the entire object so I had to find a solution to reduce the impression with as minimal intervention as possible so as not to alter the surface of the object. After it had been in storage that such a long amount of time with changes in humidity fluctuation it was thought that the wax had undergone some reaction with the Tyvek, leaving an impression as you can see in the images above. There was plenty of testing done to get to the final conclusion that the simplest way to reduce the impression was with warm water applied with a cellulose pulp poultice. The treatment is as follows:

• Dry surface cleaning with soft brushes and a document cleaning pad.
• cellulose pulp poultice with warm water
• Two rounds of abrasive cleaning with Rottenstone and water applied with a microfiber cloth
• Clearing with distilled water
• De-greased with ethanol
• Polished using renaissance wax and a microfiber cloth

For added measure the new storage for the object had used Tyvek which had been washed with two rounds of anionic detergent and rinsed 8 times with deionized water to ensure the removal of any impurities on the surface of the Tyvek. The total treatment time for this object, including various test methods was 21 hours. As you can see from the after treatment images below, there still remains a shadow of the impression which could not be fully removed.

Portable XRF analysis shows that a small amount of titanium was only present in the areas of white patches and not in the areas of the clean surface suggesting that perhaps some of the whitening agent of the Tyvek was transferred onto the stone.