by Ellen McCrady
The Institute of Paper Conservation only has its international conferences once every six years, but they are carefully planned and have a reputation for high quality papers. This time the conference was at the University of Manchester Institute of Science and Technology (UMIST), April 1-4, 1992. Most of the papers were outstanding, and most of the time it did not rain. Four days was not quite long enough to talk to all one's old colleagues, read all the posters thoroughly, and visit all the exhibitors' booths, as well as attend all the sessions, but maybe this is the way it should be. One should leave such a conference feeling refreshed, not surfeited. Several people agreed with me that it would be nice to meet oftener, say every four or five years, so we could be refreshed more often, and there was a rumor that the IPC was considering this idea.
The proceedings will not be out till next fall, so this report of selected papers and posters is based on personal notes and the abstracts in the handsome conference handbook. It will not include details on the art on paper sessions held all day Friday April 3, because I was attending the book sessions held simultaneously. Audio tapes and the published proceedings can be ordered from the Institute of Paper Conservation, Leigh Lodge, Leigh, Worcestershire WR6 6LB, England.
The posters covered a wide range of subjects, including green pigments, washing of large flat objects, clean air for a suction table, an easier-to-use substitute for sodium borohydride, mounting of parchment fragments, book lice, high production library conservation, air pollutants and deacidified paper, fixing of inks, a comparison of deacidification and other treatment methods in six countries, protein inhibitors for enzymes, permanence of coated papers, Gore-Tex, conservation of paper-covered books, and analysis of metallogallic inks. The alternative to sodium borohydride for bleaching and stabilization, proposed by two chemists from the Istituto Centrale per la Patologia del Libro, is ter-butyl amine borane; they continue to investigate its effects. The air pollutants study reported in John Havermans' poster is being carried out cooperatively by four institutions and is funded for three years by the European Community, it involves accelerated aging of new, old and deacidified paper with polluted air. The coated papers poster, by Derek Priest and two other people (students?), reports preliminary results from a project on the aging of specially coated papers. The papers benefited mildly from the coatings, perhaps because of the migration of coating components into the base paper.
Peggy Ellis's paper, "The Porous Pointed Pen as Artistic Medium," can be taken as a sign that the felt tip pen has arrived, after almost 50 years of use by almost everybody. She referred to the generic type of pen as the porous pointed pen because the manufacturers use that term- the felt tip pen is only one kind of porous pointed pen. She described the materials that go into the nibs, reservoirs and inks, and the problems in restoration of art works done with these pens. Some of the dyes in the inks will transfer to adjacent papers, even through polyethylene and multiple layers of paper, even after 26 years. Her advice: just keep changing that interleaving paper.
Faith Zieske, in "The Conservation Treatment of Two Cezanne Sketchbooks," described what she had to do to remove 40-year-old stains from pressure-sensitive cellophane tape hinges used when the individual leaves of the sketchbooks were framed. It involved solvent fumes to soften the adhesive, paring down the carrier and adhesive under a microscope, solvent application with the paper on a suction disk, and finally prevention and control of tide lines from the solvents, by use of B&P naphtha as a "border solvent."
The audience got pretty enthusiastic about the condition survey at the National Art Library (NAL), described by Helen Shenton, and urged that it be adopted as an international standard. It was actually designed by Suzanne Keene for use in all the museums of London, for books and objects. First a sample survey of the one-million-book collection at the NAL was done to see the size of the problem. The condition of each book in a 10,000-book sample was categorized on a five-point scale, from unstable to stable, and they discovered that 75% of the collection needed attention. It would have taken about 2000 man-years of work to give those items that attention, so they decided to focus on preventive measures. They did a second survey, selected the highest-priority items in a systematic way, and calculated how much it would cost, and how long it would take, with the people they had available to them (taking into account how much per hour each specialty was paid), to treat those items. A combined approach was used, giving concentrated attention to a few and minor treatment to large groups. Suzanne Keene gave a paper on this survey method at a UKIC/RAI Exhibition conference last October. Her address is: Suzanne Keene, Head of Conservation, Conservation Department, Museum of London, London Wall, EC2Y 5HN.
Rolf Dahlø of Norway, who has been promoting the use of alkaline paper in Scandinavia with buttons and other memorabilia bearing a little hedgehog and the slogan, "Say NO to acid paper!" (in Norwegian, of course), described what amounts to a Noah's Ark project, in which one copy of each book published recently will be stored inside a mountain near the Arctic Circle. Now under construction, the storage facility will be completed in the summer of 1992, and will hold a million books. There will be no expenses for heating or cooling: the natural temperature inside the mountain (8° C) is fine, and a relative humidity of 35% will be maintained for both books and photographs. So if you take just the lower temperature, and calculate (with the aid of David Erhardt's arithmetic in the June 1989 Abbey Newsletter) how much it lowers the reaction rate (rate of deterioration) from that at 22° C, you find that it will be cut by about 90%, if the activation energy is taken to be about 30 kcal. In other words, storing these books in this facility will make them last about 10 times as long. This is far better than deacidification which only makes books last two or three times as long. The Norwegian Parliament thought this was a good idea too. In December, they decided to make this cold-storage collection the first part of the new national library, which is just now being established. Anyone who wants to visit the site of this momentous development should ask the way to the little steel town of Mo i Rana, after checking first with Mr. Dahlø (National Office for Research and Special Libraries, PO Box 2439 Solli, N-0202 Oslo 2, Norway).
Tony Cains gave the first part of his history of heatset tissue, then had to quit because of time constraints. But the whole paper will be in the proceedings. The first heatset tissue was prepared in 1961 by Sandy Cockerell, and the materials and methods used to prepare it were improved and developed over the years by Peter Waters, Joe Nkrumah, Margaret Hey, Tony and others. Ways of using it and removing it were also developed.
Tony Bish, who in the 1980s has been Conservation Officer at the Royal Greenwich Observatory and Head of Conservation at the Wellcome Institute for the History of Medicine, described the work he had been doing in a very old (900 years) private library in Jerusalem since 1987. Some workmen discovered about 20,000 fragments and folios of medieval manuscripts in the attic, which have been used to reconstruct some important texts in the library in the same house. But the big problem was the bugs in those fragments. They had to be gotten rid of before the fragments could be integrated with the rest of the collection. So the books were fumigated with Lindane, of all things. In the question period afterward, he was asked why he didn't freeze them. His answer: There are freezers in Jerusalem, but they are only used for food and drink; and 1200 books take up a lot of room. Everyone there fumigates twice a year. Insects come in the library all the time. (I wondered why this paper was admitted to the program, if it described dangerous and outmoded practices for which effective, safe alternatives exist.)
Linda Lee and Christopher Calnan of the Leather Conservation Centre described a project begun in 1987 to determine whether the oak bark leather tannage used in England since Roman times could be duplicated today. Its high quality and stability are attributed partly to the slow tannage in pits, without agitation, and to the use of lime for a two-week unhairing process. Two small tanneries in the south of England were found that were willing and able to tan experimental hides the old way, and the samples were tested in the lab and in practice. They had good working qualities, but did not pass the oven aging test with sulfur dioxide gas. (The older leathers are thought to have survived mainly because of residual calcium.) Retanning with aluminum compounds did protect them against deterioration in the aging chamber but it interfered with working properties, so the recommendation is to retan the leather after it is on the book. One or both of the tanneries is willing to sell skins tanned the old way, beginning May 1992; inquire with Linda Lee, whose address is 5 South Close, Greatworth, Oxon OX17 2DZ. She can also provide information on retannage. In the question period, someone asked what they should do with the leathers they now have; the reply was to find out more about their condition. The pH and shrinkage temperature tell you a lot. A pH of 2.5 or above is required for stability. Parchment and alum-tawed skins were also recommended for their good lasting qualities.
Cathy Baker chaired a session on sizing, and in her introductory remarks warned people that hot water, alkaline treatments and reducing bleaches may wash away the gelatin sizing layer from older papers, taking the media along with it. She gave a paper of her own in this session, on how the viscosity of methyl cellulose affects its performance as a sizing. The low viscosity grades are best for internal sizing and the high viscosity grades for surface sizing. High viscosity methyl cellulose is more stable than low viscosity, and can protect the paper against acids and oils. As a surface size, it strengthens paper both before and after aging, but does not penetrate the paper well even in dilute solutions, and may cause blocking of adjacent pages. Her advice was to stock more than one viscosity- use food grades- and know the brand name, manufacturer, shelf life, purity, viscosity, date of manufacture, and maybe even the degree of substitution and polymerization, because they are not all alike. To prevent loss of viscosity, mix it using pure water and avoid contamination of stock by not returning unused portions to storage.
Irene Brückle gave a clear, detailed historical paper on the mining and preparation of alum, and its use in papermaking. The first documented use in western papermaking is from the sixteenth century. Until the invention of the paper machine and the use of internal size, it was used mainly as a preservative and hardener for glue sizes.
Kathy Orlenko described the Johns Hopkins resizing project, which used a large number of naturally aged papers. The study controlled for a number of variables (including fiber content, nature of original size and whether the paper was also deacidified in the lab), and investigated the effect of six sizes or strengthening agents on the permanence (and other aspects) of the papers. Preliminary findings include the following: 1) simple washing is often as effective as deacidification in lowering pH; 2) parchment size appears to age best; 3) deacidification baths should be monitored, so the effect can be controlled, and 4) parylene helps strong papers better than weak ones. The sizes tested were parylene C parchment size, gelatin, starch, methyl cellulose and Klucel G.
Tim Barrett reviewed analytical methods for identifying sizing agents in paper and, in a separate presentation, described ongoing work investigating the effect of gelatin sizing on the permanence of paper. Gelatin sized papers are being tested for resistance to pollution (they use auto exhaust), heat and humidity. Work done in recent decades leads to the conclusion that gelatin has a significant and strong protective effect, yet this has received little recognition. In the question period, someone asked if any conservators used Aquapel or Hercon as a sizing agent, and his answer was that cellulose derivatives were better because Hercon and Aquapel were quite light-sensitive; they lose size even if they are left out on a table over a weekend, in the light.
Dianne van der Reyden's paper (with Christa Hofmann and Mary Baker) was "Some Effects of Solvents on Modern Transparent Papers." She described work that involved not only identifying the type of paper by analytical means, the effects of aging, methods of humidification, and techniques of applying solvents in treatment, but describing methods used by papermakers in manufacturing glassine, tracing paper and so on. "Parchment," or "genuine parchment paper," is the only one for which an acid bath is used; this should calm the fears of preservation librarians who have been warned away from glassine envelopes and interleaving sheets by horror tales of acid treatments at the mill. Methods used are overbeating, repeated calendering, and use of a transparentizing impregnant or coating. An overbeaten sample became brown, weak and opaque on aging.
This same group of authors also reported the effect of three different humidification methods on this type of paper. The greatest degree of change in the papers was seen with immersion, the least with use of the suction table. Nine variables were examined.
Françoise Leclerc described the effect of optical brighteners on permanence of paper, as observed in work done with Françoise Flieder. Six types of paper, with and without brighteners, were tested and aged with humid heat and with light. Preliminary results do not show any effect of the brighteners on physical or chemical properties on any of the papers but the brightened rag pulp paper, which degraded faster, no one knows why.
Catherine Rickman spoke on philatelic conservation at the National Postal Museum and the British Post Office Archives. (The reason we do not hear very much about conservation of stamps is that so little work is being done, though the need is great. This paper may be a sign of better things to come.) At a recent stamp exhibition, she said, there was not one archival supplier. The National Postal Museum, however, is taking the lead; it is having conservation storage materials made for it, and it now has a preservation program. She described the history and nature of philatelic materials, and how this affects treatment methods. Water-soluble dyes were sometimes used in the inks, for instance, to prevent reuse of stamps.
Elissa 0'Loughlin of the U.S. National Archives gave a paper she coauthored with Linda Stiber, "A Closer Look at Pressure-Sensitive Adhesive Tapes: New Treatment Strategies." This was an overview of the history and nature of pressure-sensitive tapes, with three case studies illustrating the use of a diagnostic scheme (available as a handout) in choosing a treatment. The first adhesive tape was invented in 1845 for medical bandages scotch tape was patented in 1931, acrylic adhesives were introduced during World War II because of the rubber shortage (the adhesive in Scotch tape includes rubber with unstable rosin as a tackifier). Acrylics may include tackifiers and plasticizers, but polyacrylates do not need them; they are inherently more stable. Tapes sold as "archival" are not always archival: the film carrier may include vinyl and the adhesive may include phthalates. A non-solvent technique for tape removal is the use of controlled heat, as on a slide-warming tray. Too much heat may drive the adhesive into the paper. Chapter 15 of the Paper Conservation Catalog (available from the AIC) is on tape removal. Accelerated aging of archival tapes is being carried out now at the National Archives.
This is only a brief description of a few of the papers. Many other fine papers were presented, but are not described here because they are too hard to summarize, or because they were given in the other simultaneous sessions.