45th Annual Meeting – Textile Session, June 1, “Agarose, Two Ways: Successes and Challenges in Large Scale Gel Application” by Dana Goodin

The Textile Specialty Group audience got a real treat with Dana Goodin’s talk on using agarose gels on tapestries.  Dana, who works at the Textile Conservation Laboratory at the Cathedral of St. John the Divine in NYC, used agarose gel on two tapestries in two different ways.

The first was a Baumgarten tapestry dating to the 1910s.  It, and many others, were discovered on the walls of a townhouse on the Upper West Side of Manhattan after a developer purchased the property.  In previous years, the room the tapestries were in had been rented out as a studio apartment.  (As an NYC resident myself, you can only imagine the envy this inspired in me!)  The tapestries were attached to the wall around the perimeter with nails.  Stains from leeching plaster were prevalent and the lining had fallen down behind one tapestry, resulting in ballooning and a large slit at the bottom.  A square had even been cut out of a tapestry to access a utility box!  The tapestries were de-installed in 2013 and brought to the Lab, where there were laid flat in a humidity tent.  The humidity was maintained between 52% – 58% for many months.  This was not enough, however, to restore flexibility to the desiccated silk elements of the tapestry.  Since the silk in the tapestry was in such poor shape, it was feared it would disintegrate during wet cleaning.  It was therefore decided to clean, and of course humidify, the tapestries through agarose gel.  Dana told us that the Textile Conservation Lab would usually use a 1% density gel if the material were smooth and could later be rinsed under suction.  Because this was not an option with the silk, it was decided to also rinse the cleaned tapestry with agarose gel and deionized water.  For cleaning, 3.4% density gel, ¼” in thickness, was cast with Orvus.  The Orvus solution was 5ml to 300ml water.  The entire Baumgarten tapestry was cleaned with gel, although the wool elements received thicker gels and were rinsed under suction, rather than with gel.  The treatment was a great success: the appearance was incredibly improved and the tapestry regained enough moisture that it could afterwards be rolled without worry.

Clearly, this treatment required a lot of agarose gel, the cost of which escalated quickly.  Not to mention the time spent casting it.  Therefore, Dana and the other conservators at the Lab tried out reusing the gels.  Tests were performed on white China silk and it was found that after three rinses/soaks of the gels in Orvus, no soiling was redeposited on the test silk.  This was a great find, although it was concurrently found that the gels could only be reused three times before disintegrating.

The second tapestry Dana spoke about was an Agam tapestry from the 1970s.  It was made from white wool yarn and a variety of wool/synthetic colored yarns.  It suffered from hard glue residue on the top and bottom 2” of the tapestry, which previously attached a lining.  Complications arose from the fact that the red and black yarns bled.  The face of the tapestry was cleaned via dry surface sponging, but obviously that did nothing to address the glue, which was so hard it couldn’t be sewn through.  Tests showed that amyl acetate removed most of the glue.  Application methods tested were with blotters, cotton linters, and agarose gel.  The agarose gel proved the most effective.  Gauze was placed below the tapestry, then the gel was draped over the glue, before being weighted.  Although effective, this proved very time consuming.  To speed things up, Dana and the other conservators decided to apply the amyl acetate directly to the glue and then drape the gel over these sections with weights on top.  2% gel was used for this, and left on for one hour.  This process was repeated until as much glue was removed as possible.  The treated areas were rinsed with deionized water, and the tapestry received a new lining and a Velcro hanging mechanism.

I don’t think I’m overstating things by saying these were two awesome treatments.  Thanks for sharing them with us, Dana!