The Abbey Newsletter

Volume 16, Number 7-8
Dec 1992


Paper Preservation: Current Issues and Recent Developments. Edited by Philip Luner. TAPPI Press, Atlanta, 1990. Chiefly papers presented at the TAPPI Paper Preservation Symposium held Oct. 19-21, 1988, in Washington, DC. 150 pp. $58 to TAPPI members; $88 nonmembers. Paper binding, permanent paper, 8.5" x 11". ISBN 0-89852-500-4.

Reviewed by Ellen McCrady

This volume of edited proceedings is a decided improvement over the preprints, because some of the marginal and repetitive materials have been winnowed out and some of the 35 remaining papers have seen major editing or revision. Only eight of the papers were by people in the paper industry, but most of those eight papers are valuable contributions and new to the preservation field.

It is too bad that the copy editing was carelessly done. Typos abound, authors' names are misspelled (Henk Porck, Ingmar Fröjd, Vladimir Zwass, C. Bertil Anderson, Idelette van Leeuwen, T. Lindström, and N.M.M. Jones), lines of type appear to have been dropped in several places, and so on. Sometimes this makes it hard to understand. The editor decided not to include the abstracts or even the authors' titles and affiliations. Nevertheless, this is a record of an important meeting, and it is worth paying attention to, since it may be another 20 or 30 years before papermakers and preservation people get together again to talk about matters of mutual concern.

The papers are grouped under the following headings; the number of papers under each heading is indicated.

The first "congressional voice" was that of Representative George E. Brown, who said, "It is shameful that we still do not have a requirement that all printed federal publications be issued on alkaline paper. . . . It is humiliating and ludicrous that we have not already done this." He also expressed strong reservations about allowing the Library of Congress to develop a deacidification system, particularly one using diethyl zinc. Representative Major Owens, the second "congressional voice," summarized the role of several federal agencies in preservation and asked what Congress could do to encourage the paper industry to shift to production of alkaline paper. (The shift was well under way at the time, having begun to accelerate in 1985 or 1986, but he did not know this.) The third "congressional voice" was an early version of the national permanent paper law (PL 101-423).

Preservation Concerns

The next section covers a wide range of preservation activities: the use of alkaline paper for medical literature, research in the Netherlands and Sweden, education, micro-filming, and other remedies to the brittle paper problem. Richard Smith's "Paper in Archives, Libraries and Museums Worldwide" opens the section. He touches on storage conditions of a set of comparable books in the New York Public Library and the Dutch Royal Library, saying the Dutch books have a half-life 37.7 times longer than the New York books; he disputes the results of the book condition survey performed in 1984 by King Research for the Library of Congress, using theoretical and arithmetical arguments to show that 690,000 books, not 77,000, go brittle every year; asserts that "the doctor's approach, i.e., one doctor to one patient, illustrates general practice in preservation work today"; and concludes that the only alternative to the doctor's approach is to use machines for preservation. I found these statements mysterious and incredible, since satisfactory evidence was not presented to support them.

Richard DeGennaro and John P. Baker, in separate papers, summarized the preservation problems and solutions found at the New York Public Library from 1911 to the present, including microfilming (from the 1930s on), conservation treatment, and finally (1986) air conditioning.

Research projects in the Netherlands and in Sweden, being performed in support of national preservation plans, are described and briefly summarized. Both countries are promoting the use of permanent paper, investigating the effect of air pollution on paper degradation, and carrying out condition surveys of collections. Both countries found that a smaller proportion of their books were brittle than in the U.S. (However, at that time, reports of average embrittlement in the U.S. were probably exaggerated. Figures around 30% were being quoted, though the U.S. libraries that surveyed their collections for the ARL Preservation Planning Program in the 1980s found an average closer to 18%. That is an unweighted average which does not take into account the size of the collections.)

Sally Buchanan's paper summarized the ways librarians are coping with past paper deterioration, and described the increasing use of long-lasting paper. Charles Kalina, in a paper coauthored by Donald Lindberg, described the National Library of Medicine's Long Range Plan, in which the Permanent Paper Task Force plays a part by persuading publishers to use permanent paper. Robert Wedgeworth described the conservation education program at Columbia University, which has since moved to Austin, Texas. George Farr described the National Endowment for the Humanities' five-year plan for preservation, new at the time, and its support of microfilming, conservation, research, public awareness, state programs and training. At the time, NEH's Office of Preservation had given out 100 grants, totalling $14 million in outright and matching funds. Its big goal was then and still is to microfilm three million books in 20 years (now 16 years). Finally, William Kindler and Pat Battin summarized the approach of the Commission on Preservation and Access to the brittle book problem. These papers were intended to give a summary of preservation for papermakers, so they cover ground familiar to preservation people.

How Paper Deteriorates

The next section summarizes research and testing relating to preservation done in the paper industry and paper labs. It constitutes a reservoir of reliable, fairly accessible technical information that can be used for reference or simply read through to glean interesting facts. Librarians and archivists who want to be active in writing or implementing paper standards may even want to study and review this information from time to time.

The authors of the first paper, D.F. Caulfield and D.E. Gunderson, considerately tell readers they can photocopy their paper as much as they want to without violating copyright, because it was written on government time. It explains accelerated aging and the tests for fold, tear, tensile and burst, each of which varies with RH more or less independently of the others, because each tells something different about the paper: fiber length and strength, bonding, crosslinking, etc.

John Waterhouse, author of the next paper, is interested in the complex changes that go on in paper as it ages, especially in what we can learn from nondestructive ultrasonic testing about these changes. (He worked with Tim Barrett in his analysis of early European papers. This analysis showed that papers in good condition were easily identified by ultrasonic testing, and that they had more gelatin sizing than the papers in poor condition.)

Waterhouse's writing style is too technical for most nonscientists, and sometimes he omits points that are necessary for understanding. His tables and graphs, most of them reprinted from both paper and conservation literature, are interesting. The most thought-provoking one may be a table from a 1979 paper by Wilson and Parks in Restaurator, giving 18 tests that can be used to track five reactions or changes (hydrolysis, oxidation, crosslinking, thermal decomposition and bonding "order" decrease) over time. The last one includes bonds formed by sizing agents. Waterhouse has his own list of five degradation mechanisms that have been investigated by other researchers. The first four overlap with those in the above list, but instead of the last one he lists photochemical degradation.

Howard Rapson and two coauthors report the effect on pulp whiteness of different bleaching methods, after 17 to 29 years of natural aging. (Strength was not tested, only color.) Sodium hypochlorite (sold in dilute form as "chlorine bleach" in the supermarket) at pH 7 darkened even 100% cotton linters to what must have been a brown shade, to judge by the post-color number of 142. Chlorine dioxide, though, caused very little darkening.

The biggest factor in yellowing with aging is the presence of carbonyl groups (CO) on the cellulose molecule, a result of oxidation; treatment with a little sodium borohydride, the authors say, after any bleaching sequence will reduce these groups and minimize yellowing. Some of the pulp samples were aged with heat or gamma radiation before natural aging. The gamma radiation greatly increased yellowing. The authors suggest, "Along with humidity and temperature, it is suggested that high energy radiation from the environment and from outer space may contribute to the yellowing of paper with age."

David Erhardt's six-page paper, "Paper Degradation: A Comparison of Industrial and Archival Concerns," is really about accelerated and natural aging, and would be good to keep handy after the first reading, because he covers most of the points about which people argue, or wonder, or have reservations. He addresses, for instance, the question of which range of aging conditions produces changes most similar to natural aging. (There can be no clear answer at this stage, he says, but he cites relevant research and discusses different ways of evaluating aging conditions.) He also discusses causes of degradation: temperature, relative humidity, light, indoor pollutants, oxygen (yes, oxygen), and the deliquescent salts formed in paper when alkaline buffers like calcium carbonate are neutralized by acidic gases.

A Dutch government survey and analysis of air pollution and paper condition in cultural institutions is reported by Henk Porck and coauthors in "Research on Mass Conservation of Archival and Library Materials." The mass conservation referred to in the title is not a form of mechanical treatment as it suggests, but environmental control of gaseous pollutants. At this stage they were measuring concentrations of sulfur dioxide, nitrogen dioxide and ozone in archives and museums, and measuring the pH of newspapers and books.

It is ironic that this work was being done not in the U.S., where books suffer so much from pollution, but in the Netherlands, where the environment is so benign that the outer margins have a higher pH than the centers of the pages; in other words, the degradation products of the paper itself do more harm to the paper in that country than do the gaseous pollutants and all the other factors that affect principally the outer parts of books. The evidence on this is pretty convincing. It was based partly on the condition surveys performed and partly on comparative analysis of the same set of books discussed above by Richard Smith. Two sets of identical books printed on groundwood paper, one set stored for most of a century in the New York Public Library and the other in the Royal Library, were brought together like twins reunited in old age and compared. Besides having opposite patterns of pH variation on the page, they differed in the pH of the page margins (2.8 vs. 4.0) and in the average of the readings on each page (3.1 vs. 3.9). A great deal of data is presented in this paper, and it all seems to say that, compared to the U.S., the Netherlands has no serious paper preservation problem. The study will continue, and should produce other interesting reports in the future.

Tom Lindström, in his discussion of how paper deteriorates, has his own list of mechanisms, different from Wilson's and Waterhouse's. The first three (hydrolysis, oxidation, crosslinking) are the same, but he adds microbial degradation, mechanochemical degradation, crystallization and physical volume relaxation. In his own condensed, epigrammatic style, he lists the many known ways in which hydrolysis and oxidation interact and accelerate each other. He makes a good case, but does not trace the implications, that is, he does not show how this phenomenon affects anything we do either in research or in practice. Because paper aging is such a complex process, he says, with many reactions going on at the same time, each with its own activation energy, accelerated aging should not be expected to tell us how long a given paper will last. He does admit that Wilson and Parks' 1980 study in Restaurator demonstrated a correlation between natural and accelerated aging.

Philip Luner, editor of the volume, in his own two-page discussion of aging, lists eight chemical reactions: hydrolysis, oxidation, crosslinking, dehydration, new C-C bonds, C-O-C bonds, and possible increases in glass transition temperature and crystallinity, which (he said at the time) are difficult to detect but may be important. He lists eight consequences of aging:

In his preface he emphasizes that "the papermaker, librarian and conservator should continually evaluate new developments in paper manufacturing to insure that the gains made by converting to alkaline papers are not offset by other technical developments that may be detrimental to paper longevity." He spoke at greater length on this subject at the 1988 conference, suggesting trends to watch:

Steve Walkden's paper ("Permanence and Durability of Paper") gives a rosy picture of alkaline papermaking, which does in fact have many benefits for both papermaker and consumer, but which is not simpler than papermaking in an acid system as he says, and does not necessarily produce a stronger sheet, especially at the higher filler levels in use today. He does present some hard-to-find information about alkaline production as a percent of the total in grades other than printing and writing paper, and he compares European and U.S. percentages. In 1987, a quarter of all sized packaging in the U.S. (much of which was going into production of milk cartons) was alkaline, as was about a seventh of all sized board. In Europe, the percentage of paper and board made alkaline was two to three times as great as in the U.S. in every category but packaging, where our percent was twice as great.

Anthony Liberatore's paper gives a brief history of Glatfelter's conversion to the alkaline process 1966-74; it also gives the advantages of alkaline papermaking, and has breakdowns of printing/writing and book publishing production by end use and market segment. Two of his tables give the types of coated and uncoated freesheet and groundwood sheets on the market, with an estimated permanence rating for each. His typology cannot be complete, however, because it omits all papers coated with clay, although they made up a good portion of the market in 1987.

Samuel B. Skaggs of the Government Printing Office defended the use of acidic paper in a presentation full of errors and false assumptions concerning alkaline paper availability, the nature of permanence, and even the membership of the technical subcommittee responsible for government paper specifications, which he augmented by adding the name of a deceased person. His paper drew criticism from the audience, but he stood his ground. (A year or two later, the GPO started inviting bids for alkaline paper, in response to the permanent paper law which was still working its way through Congress at the time.)


Rolland Aubey has a paper on the ten leading standards and test methods relating to paper permanence, in which he not only lists each standard but gives their major requirements. Since his paper was given, two of those standards have either had major revisions or been dropped (ANSI PH1.53 and ISO 5630 pt. 2). (Revisions of standards, by the way, are something that should be--but often are not--noted by everyone who uses or cites standards. The state of the art changes constantly, and the 1972 edition [say] of a standard is not the same as the 1990 edition. That 1972 edition may be worse than nothing, because it gives a false feeling of security while encouraging the use of methods that may be outmoded and counterproductive.)

Gerhard Banik and Werner Sobotka's paper, "Standard Specification for Permanent Paper in Austria," describes standards activities in Europe. Austria's 1987 standard for permanent paper has several interesting features: 1) it forbids the use of recycled fibers, 2) it permits manufacturers and others to label conforming paper with the name of the standard, "NORM A 1119," c) it was based on the ANSI standard, Z39.48-1984, and d) it will form the basis of a forthcoming European Community standard (which is not yet completed as of 1992--they are waiting to see what ISO will do). (The authors also claim that it is the first European stan dard for permanent paper, but what they must mean is that it is the first to emphasize pH and alkaline reserve, rather than fiber type, because Sweden published a standard for permanent paper in 1964 or so, and there must have been others before that in various countries.)

The Austrian standard has two requirements that are not in the ANSI standard: that any fillers must be free of oxidative catalysts like iron, and that additives must not adversely affect the permanence of fibers. Those requirements sound good, but how can they be enforced by the purchaser, and how can the papermaker tell what the long-term effects of additives will be? They or their suppliers will probably use oven aging to test the additives, but routine oven aging does not answer all questions. The vulnerabilities of the material undergoing testing may have to be explored, so that the aging conditions can be chosen to provide realistic answers. Some effects are provoked with light rather than heat; others occur later on under other, presumably safe, conditions, or like rubber cement, after a period of latency during which the material appears to be stable; others, such as degradation from gaseous pollutants or storage in contact with otherwise harmless materials, occur under conditions not present in the aging chamber. Perhaps this concern is addressed in the Austrian standard, or acknowledged by the committee that drew it up. In any case, those two requirements are a step in the right direction, and are the only evidence that anyone anywhere is addressing Phil Luner's concern about the effect of new additives on permanence.

Book Preservation Technologies

The last section is composed mainly of updates on deacidification and strengthening processes in use or being developed at the time: an overview by Richard Smith, and descriptions of the DEZ, BPA, Bookkeeper, parylene, aqueous-immersion-and-freeze-dry, Wei T'o, and graft copolymerization processes. These have been covered in more recent publications, so we need not dwell on them here. But two unusual papers in this section call for attention: "Lamination and Encapsulation for Paper Strengthening," by Norvell Jones, and Jerome Brezner and Phil Luner's "Preservation of Library Material by Microwave Radiation," originally entitled "Preserving Books from Living Pests" and authored by Brezner alone.

Some people were surprised that Norvell Jones would discuss cellulose acetate lamination as a legitimate preservation method, because its reputation has suffered from the days when it was overdone and used inappropriately. Many institutions gave it up when the Library of Congress dropped lamination in favor of encapsulation in the early 1970s. However, she says, when sheets are first effectively deacidified and minimal press temperatures are used, "results are durable and apparently relatively permanent. At this point, published research data does not exist to refute the claim of permanence of the predeacidified laminate." The problem is apparently to maintain quality standards in the use of the process. Things can go wrong (e.g., plasticizers in the film may cause colors to bleed), and delamination, when it is necessary, is tedious and can be risky for the document.

Encapsulation between sheets of polyester appears to be simple and safe, but has drawbacks of its own. No single technique, she points out, is suitable for every item needing preservation. The choice of treatment for an item has to be based on a number of factors, including the reason for which it is being preserved; deacidification should precede enclosure by any method, if practical; and cost has to be weighed against benefits.

Jerome Brezner had promised at the 1988 symposium to turn his paper into something "scientifically more acceptable," and he and Phil Luner have in fact thoroughly rewritten it. Brezner is apparently an entymologist, who started to work on this idea after being called by a librarian interested in protecting books against pests and mold. The librarian was considering zapping them with gamma radiation, a scary idea because of the high doses necessary to kill certain insect pests. As a safer alternative he proposed the use of microwave ovens, which he says can be used both to treat material in the stacks and to prevent introduction of pests through book return channels.

His original proposal was given space in newspapers across the country, but was not seriously considered by preservation librarians. In fact, some of them were horrified by the idea, because of the probable effect on the books, especially if every returned book had to be routinely microwaved by student workers (librarians delegate all repetitive work); and there would be sparks from staples and security strips, not to mention scorching from uneven heating, especially on books returned in damp weather.

The authors are apparently unaware that returned books are not a problem source of insect infestation in U.S. libraries. They recommend that all shelved material be microwaved to start with, using a commercial sized unit into which carts could be wheeled, or through which a conveyor belt might run; do they realize that some libraries have millions of volumes in them, and that there are ways of finding out whether an infestation exists before going to all that trouble?

However unfamiliar Brezner and Luner may be with library operation and with the advantages offered by the pest control methods already used in library preservation programs, they have made a useful contribution here. They have surveyed the literature on the effect of microwaves on bacteria and fungi (virtually no effect), protozoans (some) and insects (lethal). Microwave radiation has been used to dry wet paper and books, but it is not recommended for coated or recycled paper.

They also did their own preliminary study of the effects of microwave radiation on books and magazines, and on the microorganisms and insects inside them. The study is intended to set basic parameters for such treatment by investigating how much radiation, for how long a time, is necessary to kill 50% of dermestid beetles and confused flour beetles in books of various thicknesses. The effect on the books themselves was noted but not quantified. The only change observed was slight charring from a paper clip at the edge. (A longer period of radiation would be necessary to achieve 99% kill. One wonders how dark the charring would have been then.)

Future research is outlined and a program of insect control is recommended. In order to orient the research toward useful application, it should probably be done in partnership with knowledgeable and motivated librarians and some of their current technical advisors.

Conservation of Plastics: An introduction to their history, manufacture, deterioration, identification and care, by John Morgan. Plastics Historical Society and the Conservation Unit of the Museums and Galleries Commission, 1992. 55 pages. £7 + £1 shipping from Archaetype Books, 12-14 Hall Square, Denbigh, Clywd LL16 3NU, UK (Fax 0745-815484). NB. This number is inaccurate and a correction printed in v.17, number 1. The correct number is 0745-813484

Reviewed by Alan Calmes, Preservation Officer of the National Archives and Records Administration and author of "Practical Aspects of Plastics Found in Archives," Restaurator 13: 23-35, 1992.

Conservation of Plastics is an excellent book, useful to anyone in an archives, museum, or library, especially when dealing with non-paper recording media, such as sound recordings, motion picture film and computer tape. Of course, it is a must for anyone interested in 19th and 20th century plastic artifacts.

This small booklet is packed with insightful information about the history and characteristics of each plastic. The main entries of the table of contents are:

Under the main entry there is a list of subordinate plastics, such as shellac, under "Plastics Based on Natural Polymers," cellulose acetate under "Semi-synthetics," and polypropylene under "The 'Poly' Era Thermoplastics," to mention only a few. Popular names or trade names of plastics are referenced to their scientific names; for example, polyester is often referred to as Mylar, a DuPont registered trademark, but more accurately it is polyethylene terephthalate. There is also a list of "Acronyms for Plastics" at the back of the book; for example, PET stands for polyethylene terephthalate. Dates of introduction and aging characteristics for the various plastics are given to aid in conservation.

Throughout the book the main culprits of degradation are evaluated for each type of plastic. Light, temperature, and ventilation are emphasized in the introductory summary; "Identification" and "Method of Manufacture" also are sections that provide useful information for understanding the characteristics of each type of material.

Get this book! It does not cost much; it takes up little space; but it is full of useful and accurate information.

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