AIC's 41st Annual Meeting-Workshop, May 29, "Plastics Last Longer if Treated with Intelligent Conservation", by Yvonne Shashoua and Thea van Oosten

I have a fascination with plastics, I guess it’s partly because the array of materials that can be chemically engineered seems to have infinite possibilities. Objects of many textures, shapes, colors and applications exist because of plastics. Unfortunately, their existence creates challenges to both preservation and sustainability. As works of art or material culture, conservators want to make them last for as long as possible, but the most long-lived plastics also pose the problem of disposal. The types of plastics that are most likely to break down in the environment are also crumbling to bits on the shelves of collectors and institutions.
This year’s AIC meeting featured a workshop presented by Yvonne Shashoua and Thea van Oosten, two well-known experts in the field of plastics in museums. Shashoua’s book, Conservation of Plastics: Materials Science, Degradation and Preservation, is a good reference. Both Shashoua and van Oosten were part of the 2008 European POPART initiative, (Preservation of Plastic Artifacts in museum collections), which selected a few types of plastics used in artwork, studied their deterioration pathways, and possible methods for their preservation, cleaning and repair.
To begin the workshop, we were presented with a historic overview of many types of plastic materials encountered in collections. From gutta percha to polyester we learned of the properties and uses of different polymers. Van Oosten had an entertaining way of categorizing plastic types by their properties into three snack food groups; gummy worm, chocolate bar, or cookie. Gummy worm plastics are in the elastomer category, which includes both natural and polyurethane rubber.  These materials are stretchy and flexible at room temperature. Chocolate plastics are the thermoplastic category, which includes polyethylene. These materials polymerize through addition and can be melted and reformed into new shapes. Cookie plastics are in the thermosetting category, which includes Bakelite (phenol formaldehyde), melamine formaldehyde and Vulcanite. These plastics are formed by condensation reaction with water being lost, and they cannot be reformed into new shapes with heat.
We learned that it is important to know what type of plastic you have before you attempt any repairs, because an adhesive that might work with one polymer will dissolve another. To help determine the appropriate adhesive, one should consult the Hansen or Hildebrand solubility parameter for the given plastic.  The strength of bond needed, the viscosity of the adhesive and the elasticity of the plastic are other factors to consider. For lightweight polyurethane foam, water based adhesives commonly used in conservation are often adequate. Clear plastics, like polystyrene or polyester may require consideration of the refractive index of the adhesive in order to make an invisible joint.
In the afternoon we split into two groups. We had time to experiment with adhering and mending a variety of plastics, and test cleaning cloths, pads and swabs for cleaning plastics.  According to results obtained from the POPART study, it is important to clean plastics as soon as possible when they become soiled, since particles may migrate into the plastics and become impossible to remove in a few short weeks. At the same time a soft cleaning cloth must be used that won’t cause abrasion to the plastic being cleaned. My experiences in this workshop highlighted the importance of testing on mock-ups!
The four plastics at greatest risk of deterioration are cellulose nitrate, cellulose acetate, plasticized (flexible) polyvinyl chloride, rubbers, and foams. Cold storage is typically recommended for these materials. The leaders of this workshop also recommended use of an oxygen scavenger in encapsulated packaging for preservation of rubber. Rubber in collections is rapidly deteriorating by oxidation, which causes it to turn yellow and brittle.
Along with POPART a number of research projects have brought the needs of plastics collections into the spotlight in recent years; however, it is clear that more research on active conservation methods is necessary. There is so much more to learn about fascinating plastics!

AIC's 41st Annual Meeting, Book and Paper Session, June 1, "Tips Session: Contemporary Treatment Tips and Techniques" by Moderator Sarah Reidell

This year’s Book and Paper Group tips session was truly impressive. The whole session was jam-packed with helpful hints and I found myself in frantic note taking mode, trying to record all of the great advice. In just over an hour, eleven “tippers” presented an array of useful descriptions of experiences, treatment methods, housing projects, and emergency preparedness information. Everyone had great visuals with photos and diagrams, physical examples to examine, and even take-away samples.
Several tips had emergency preparedness and response in mind. First, we learned of Laura McCann’s experience with the flooding in NYC as a result of Hurricane Sandy. When the East River overflowed and completely submerged a medical library’s records storage, the materials were not accessible for weeks! The importance of prior planning was highlighted. When power is lacking, it is extremely useful to have headlamps and absolutely necessary to have your emergency plans accessible at home. Consideration of priority collections, BEFORE the stress of an emergency situation, was emphasized. Those in attendance were able to collect a sample of a TEK wipe, which is absorbent and reusable. Also on the topic of emergencies, Emily Rainwater explained how Karen Pavelka tested the effectiveness of polypropylene fiber pads for absorbing oil, a common contaminant in flood water. These pads attract oil, but repel water. Finally, Roberta Woodrick showed us how to creatively use hairpins to attach Colorplast awnings as a shield for library shelving in areas with recurring leaks.  She had also built a mobile humidity chamber of ¼”acrylic sheet and furniture movers with wheels, in order to humidify large architectural drawings.
There was a presentation on lead white reversion by Amy Hughes, which lead to some interesting commentary and discussion of the mixed results several conservators had experienced when trying to reduce the discoloration of lead white pigments. As might be expected of an oxidation-reduction reaction, hydrogen peroxide treatment to improve discolored lead pigment may be temporary. There was suggestion that inpainting over discolored lead white is a viable option that should be considered. In any case, it seems important that conservators communicate the reactivity of lead white to clients and curators to warn of possible changes after treatment.
For reducing mineral deposits on paper, Karen Dabney demonstrated how “huffing” into a beaker of deionized water produced an effective solution of carbonic acid (pH 4).  Her before and after images revealed just how effective this could be, but be careful not to hyperventilate if you try this yourself!
Judy Walsh was not present, but she created some impressive diagrams of a method of creating a cheap and effective suction disk for treating individual book pages, while still bound.
Renate Mesmer provided some examples of neatly engineered storage enclosures for a hanging wax seal and a sliding tray for a vellum manuscript broken in half, inspired by the mechanics of a pop-up book. She also had a video of how a hot air gun can magically correct errors in folds and angles when making book exhibit supports of Vivak (clear thermoplastic sheet of polyethylene terephthalate).
These were some, but not all, of the tips we heard this year from BPG members.  Thanks to all of the tips contributors; Shelly Smith, Beth Doyle, Renate Mesmer, Karen Dabney, Deborah Rohan, Judy Walsh, Jamye Jamison, Karen Pavelka, Roberta Woodrick, Amy Hughes, and Laura McCann, and many thanks to Sarah Reidell for moderating.
Look for these tips and more, to be published in the next BPG Annual.

AIC 41st Annual Meeting – Research and Technical Studies Session, June 1, "The Role of Polyester Film Encapsulation – With and Without Prior Deacidification – On Paper Degradation by William Minter and John W. Baty"

William Minter and John Baty presented the results of this aging study of particular relevance to those of us working with archives and library materials. The hypothesis: “Encapsulated acidic sheets will degrade faster than unencapsulated sheets”. The question driving the testing was whether deterioration products from the paper can become trapped in the encapsulation, thereby accelerating further damage. In essence, do encapsulated papers “stew in their own juices”?  I, for one, certainly would have assumed the answer to be “yes”. But the use of encapsulation as a means of support for brittle and fragile documents beats lamination with cellulose acetate, as would have been the practice decades ago. What else is a paper conservator to do?
Here is how this study proceeded: Minter and Baty acquired different naturally aged papers for use in this study of the effect of sealing papers between film. The papers were typical of those in archives, including bond paper, ledger paper and “onion skin”. All were acidic prior to oven aging. To more accurately mimic natural aging, the temperature used during aging was 45°C instead of the more commonly used 60°C and papers were heated for a longer period of time than normal. The aging “oven” was a sealed glass box with a circulating fan, heating element (pad?), and saturated salt solution that maintained a moderate relative humidity. If you have never been in the market for an official accelerated aging oven, you may be surprised to learn that they cost a pretty penny; we’re talking 10k! Fortunately, this alternative oven was significantly cheaper, and performed very well, consistently maintaining both temperature and RH.
 The primary method of checking the papers’ deterioration was by measuring degree of polymerization with size exclusion chromatography. Shorter hemicellulose chains in paper samples after aging equate to loss of strength and flexibility in the paper, properties that were also measured and evaluated with fold endurance and surface pH.  Results showed that the encapsulated samples DID NOT age faster than the unencapsulated samples, contrary to the hypothesis! (Maybe some of you will sleep better at night having learned this fact?) I believe this test concluded after 33 weeks. If appropriate, It would be interesting to learn if an even longer aging period would yield the same result.
A second set of aging tests with the same papers revealed that either washing in magnesium carbonate or using a non-aqueous spray deacidification product prior to encapsulation would be equally protective of some papers. It is not known how long this protection would last, however.
This was a very relevant study, the importance of which can be well appreciated by many in the field of archives and paper conservation. A repeat study of a broader range of papers, (maybe photographic?) could also yield very interesting results. For me, this is an essential paper to file under “must read, and read again”.

AIC 41st Annual Meeting – Book and Paper Session, June 1, "Update on Digital Print Preservation Research: What We Have Learned So Far About the Permanence and Preservation of Digitally Printed Books by Daniel Burge"

Digitally printed books are still in their infancy, with the onset of personal, customized and on-demand publishing, made possible in part by the internet. As they have become widespread, the understanding of their aging characterestics must be understood. This is made more critical by the variety of techologies and materials used, as well as the fact that many of the books published may be very small editions, or even one-of-a-kind, as with photo books.
Daniel Burge explained the results of some of the tests performed by the Image Permanence Institute in Rochester. Their tests examined digital inkjet books printed with both dye and pigment inks and electrophotographic books printed with dry and liquid toners. The aging tests compared the humidity, heat, pollution, light, abrasion and water resistance of digital books to traditional offset printed books. These comparisons may be used to evaluate whether the books made with modern technologies need a different standard of care than is provided to older books.
These tests specifically focused on bound materials and are not to be used to evaluate the permanence of art/photo prints or single documents. One critical issue is the material used for the technology. Often, papers must be specifically prepared (optimized) with a coating suited to the printing process in order to improve print quality and permanence. The use of alkaline paper and recycled paper was found to be on the rise, and these could be factors influencing digital book preservation.
In general, the good news is that digitally printed books do not appear to require widely different preservation environments than traditional books. Although they are far more vulnerable to water damage, they generally have equal resistance to humidity, heat, and pollution as do traditional offset books. They also have better resistance to light and abrasion, compared to offset. The vulnerability to water highlights the need for more study and planning regarding disaster and recovery techniques for digitally printed books.
For more information, see the DP3 (Digital Print Preservation Portal) project website.

AIC 41st Annual Meeting – Textile Session, May 31, "Emergence of 'Antique' Synthetic Textiles by Ebenezer Kotei"

Ebenezer Kotei, Objects Conservator for the Hagley Museum and Library, provided an informative overview of the history and use of the earliest synthetic textiles. The earliest man-made textiles began with the production of Rayon, a silk-like filament, created in France in 1884 from regenerated cellulose. Rayon and the other early man-made textiles have come of age. Nylon, the first truly synthetic fiber, is now celebrating its 75th year. (An exhibit that focuses on the history of nylon is currently on view at Hagley.)
Although the name nylon was never trademarked, Du Pont produced other polyamide fibers for different uses, among them are Quiana, used briefly for luxury clothing, Kevlar for bulletproof vests, and Nomex, used as a waterproof barrier layer with the ability to transmit  vapor. Nylon fiber textiles are to be found everywhere; from women’s nylons, fine gowns, bed-sheets, children’s clothes, sportswear and uniforms, to parachutes and blood bags. It was by far the most widely used and successful of the first synthetic and semi-synthetics (as compared with rayon, acetate and acrylic).
Mr. Kotei points out that these materials have crossed into the category of antique and that it is time to focus on them and evaluate them more closely to determine how these materials have aged, rather than simply viewing them through the romantic lens of time. His concern is partly due to the fact that many of these early fibers in their very first synthesized formulations were Du Pont company creations, now part of the Hagley collection.  Although acrylic and nylon fibers appear to be quite durable, other textiles have vulnerabilities. Some examples of the problems occurring with man-made fibers are; Rayon is prone to mildew and silverfish; Spandex (polyurethane rubber) is prone to yellowing from heat, light and nitrogen gas.     
An Institute of Museum and Library Services grant has allowed for the evaluation of these early textiles in Hagley collections by textile conservators in order to identify recommendations on storage and care for these early textiles. Researchers may find additional information on DuPont fibers in the Hagley Library.