Artifact Conservation and Preparation at CHM

Holly Lundberg, senior conservator: Some of the more difficult materials to care for are those made from certain plastics. Specifically, those made wholly or in part from cellulose acetate, cellulose nitrate, polyurethane, and polyvinyl chloride. Deterioration of these materials is irreversible, and once an object made from one of these materials begins to degrade, the deterioration can progress quite quickly. Sadly, there is currently no remedy for the chemical deterioration of these materials so all that we can do is try and slow down the rate of decay and make sure that they are not stored or displayed in contact with or near materials that can initiate and/or accelerate deterioration.    

Julie Benner, assistant conservator for costume and textiles: For a textile conservator, it can be very difficult to care for historic silks, especially from the 19th century. Dyeing and weighting silk fabrics with metallic additives was very common at that time, and the metal compounds can accelerate deterioration much more than if the silk was not treated in this manner. Silks in this condition can “shatter” with even the lightest handling. 

Liz Sorokin, conservator for paper and photographs: Scrapbooks! They contain a wide variety of materials, all jammed into one object. Many items in scrapbooks are not meant to last in the first place—think ticket stubs, newspaper clippings and silk ribbons, etc.  You often have adhesive failing, so pieces fall out of the scrapbook as you turn the pages, while other materials shift and get damaged in the handling process. Often the pages themselves are cheaply made and over time become very brittle, leading to breaking and tearing as you flip through the book. It’s a challenge to maintain the accessibility of scrapbooks without causing more damage to the object itself.  

Holly Lundberg: Hands-on conservation treatment is at best a slow, methodical, and thoughtful process. It is undertaken to stabilize or preserve objects to make them accessible for exhibition, research and/or publication, and to prevent further damage and deterioration. It involves in-depth inspection, analyses, and direct physical or chemical intervention, all of which is carefully documented. One of the more time-consuming projects that I worked on was at another museum, where I had to remove an insoluble clear coat from a large collection of 19th and early 20th c. Tibetan silver jewelry. The coating was applied to the jewelry during a previous treatment (likely in the 1970s). It was a new product with little to no testing of its viability for use in the conservation field and applied to the silver elements of the jewelry to protect it from tarnishing. Over time the coating failed and cracked in spots, allowing tarnish–causing pollutants and environmental factors to interact with the silver and a type of filiform corrosion to occur. The coating was insoluble in any solvent, so I spent about a year working under high magnification to mechanically remove the coating from the surface of the metal using chisel tipped needles and a scalpel. 

Julie Benner: Sixteenth century Flemish tapestry (not at CHM)—not only due to the aged state of the fibers and the stress from hanging upright over long periods of time, but also because in its long lifetime there were previous campaigns of repair that had to be removed because they were causing stress to the original materials or obscuring the image. Sometimes dealing with previous repairs or restoration can take as long as stabilizing the original materials.

Liz Sorokin: I once treated an unstable watercolor sketch that was mounted to an acidic backing. The treatment involved first consolidating the flaking paint layer. Consolidation involves working under magnification for weeks, applying dilute adhesive with a super fine brush under lifting paint and gently pressing the paint back onto the paper. Once the paint was stable, I flipped the painting face down and removed the backing. Backing removals happen when a piece of paper (like a watercolor painting or a historic photograph) is directly adhered to an unstable backing board. Over time these boards deteriorate, becoming acidic and warping, leading to damage of the primary object. When this happens, the backing needs to be removed by carefully scraping off the material with a scalpel. Depending on the size of the object and thickness of the backing, this can take days to weeks of slow and careful scraping. It’s also messy! You end up covered in backing dust by the end of the day. Due to the size of the object, the backing removal took weeks. Once it was all said and done, I had done a huge amount of treatment and the sketch looked exactly the same from the front as before I started—and that was the goal! 

Avoid attics, basements, and garages as storage areas. These areas fluctuate dramatically in temperature and humidity. For the most part, artifacts are “comfortable” under the same conditions that people are. So, if you have something that you value greatly, find a place within the main areas of your home to store it and protect it from dust. Be mindful of exposure to direct sunlight. Light degrades sensitive materials such as textiles, feathers, basketry, prints, drawings, watercolors, manuscripts, and color photo prints, and this damage is not reversible.

Conservators always opt for preventive conservation measures over hands–on treatment where possible. When treatment becomes necessary, conservators do not attempt to restore or return an object back to its original condition. Instead, we strive to stabilize an object to slow down or prevent further deterioration and to preserve the object in its current condition in order to maintain the cultural, historic, and scientific integrity of the piece. Sometimes objects have been altered or even damaged over time in ways that have changed their original form, but even these changes can be considered part of the object’s history. Working closely with curators and using knowledge about the object’s origin, use, and other historical sources can all help make treatment decisions.

If an object is too fragile or unstable to be displayed in the galleries, it still holds intrinsic, scientific, historic, and/or cultural value and, under most circumstances, is kept in the collection to be made available for research, publication, and educational purposes.