The Abbey Newsletter

Volume 20, Number 7
Dec 1996


Literature

Note: The classification number that follows each entry is there to help the editor arrange, file and find the citations.

When the publisher's address is not given, it can usually be found in the list of Useful Addresses that is mailed out yearly to subscribers.

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"Bibliography of Standards and Selected References Related to Preservation in Libraries," compiled by Suzanne Dodson and Johanna Wellheiser, Feb. 1996. This is on the Web, and can be accessed at the National Library of Canada's home page: http://www.nlc-bnc.ca/resource/presv/eintro.htm. (1B)

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Training for Collections Care and Maintenance: A Suggested Curriculum. Vol. 5: Library and Archives Collections. by Karen Motylewski and Lisa Fox. Published by NEDCC and NIC, 1996. 94 +24 pp. Available through NIC for $21.25 (members) or $25 (nonmembers). Contact the National Institute for the Conservation of Cultural Property, 3299 K St., NW, Suite 602, Washington, DC 20007-4415 (tel. 202/ 625-1495; fax 625-1485).

This publication is intended to guide groups that are planning to offer courses or workshops on collections care, whether they have in mind a full-scale collections care course or a short workshop. It is also for institutions that are upgrading their staff training programs. A product of NEDCC's coordinated workshop series entitled Managing Preservation, it was presented over the course of a year in 1993-94. It is also being presented this winter at NEDCC. The way the course works is described in the June Abbey Newsletter, on p. 18.

The curriculum covers preservation administration, emergency preparedness, collections maintenance, selection for preservation, and preservation management. The first 10 pages give good general guidelines to the organizers and instructors. Each of the 25 segments in the course are outlined, appropriate methods of presentation are named, handouts and supplemental readings listed, and general comments made. Twenty-eight pages at the end give instructions for homework to be brought to Session 4, a table of costs of preservation activities and 24 pages of a planning form, with cells for recording actions, costs, values, etc., on about 450 preservation activities for the next four years in the student's institution.

There are a few omissions and ambiguities. There is no index. In Segment 17, "In-House Repair and Professional Conservation," under "Space and equipment," no mention is made of a sink or fume hood. The kinds of repair done do not include spine replacement or board attachment; apparently, only the simplest operations are to be taught. (Boxmaking is in another segment.)

Mass deacidification is covered in Segment 21. Only one procedure, diethyl zinc (DEZ), is mentioned by name, although it is obsolete, since the only company that offered it has gone out of this business entirely. None of the other deacidification methods that are realistic choices are mentioned.

Segment 24, "Planning and Management," is quite detailed, however, and includes in its six pages much material that is not made explicit in other manuals or guidelines. Almost two pages is devoted to fund-raising. (1D4.2)

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"How to Negotiate the Legislative Process: A Washington State Perspective," by George W. Scott. Archival Outlook, Sept. 1996, p. 12-13.

The author is the Washington State Archivist, and an experienced state legislator, who knows how to lobby for funds (he refers to it as "outreach"). Here he lays out his method, step by step, under the following heads:

Start with a "statement of need," as do professional fundraisers.

Prepare your legislation, and visit the staff of the key committees.

Educate and enlist the boss; keep his/her staff apprised.

Leverage timely events [such as natural disasters].

Deliver. (1M)

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Martin Strebel of Switzerland has published a preservation manual for archive, library and museum collections, in two editions: German and French (Konservierung und Bestandeserhaltung von Schriftgut und Grafik: Ein Leitfaden für Archive, Bibliotheken, Museen, Sammlunge, and Conservation et sauvegarde des biens culturels libraires, documentaires et des oeuvres graphiques: Manuel pour archives, bibliothèques, musées, collections).

These volumes are distinctive in several respects: both are 11.75" tall and only 4.25" wide, a format well suited to lists of things, and in fact, this is what they contain. The first half of each book contains lists of do's and don'ts on the following subjects, on the left-hand page only: general principles, location, furniture (shelves etc.), boxes, envelopes, handling, exhibitions, environment, light, shelving practices, collections care, water disasters, regulations for use, photocopying, writing utensils, and microfilms. Here is an example from the "location" list of do's and don'ts, to illustrate the format. The "don't" is given first:

Vermeiden: Sie, dass sich Magazine und Lesesäle durch die Einwirkung der Sonne aufheizen.

Nutzen: Sie spezielle Hitzeschutzfolien an allfällig vorhandenen Fenstern.

After the do's and don'ts comes a basic bibliography, containing brief, recent, well-chosen references, mostly from the English-language literature. Then comes a list of supply sources. For each type of supply, the German version refers to at least one source in each of three countries: Switzerland, Germany and Austria. The French version does the same for Switzerland, France and Belgium. Then the sources are listed alphabetically, with address, phone, fax and occasional comments. The glossaries have only 20 terms, but they are expertly defined, and the definitions are followed by explanations of the role of that particular quality or entity in preservation.

Each volume is 89 pages long. The German edition can be ordered from the Schweizerischen Verbandes für Konservierung und Restaurierung, Route de Chantemerle 8a, CH-1763-Granges-Paccot, Switzerland. The French edition is being distributed by the author: Martin Strebel, Bahnhofstrasse 15, CH-5502 Hunzenschwil, Switzerland (tel.: 41 62-897 39 70; fax: 41 62-897 00 46). ISBNs are, respectively, 3-9520984-0-X and 3-9520984-1-8. Fifteen experts consulted with the author on the German edition, including Dr. Gerd Brinkhus, Sebastian Dobrusskin, Olivier Masson, Dag-Ernst Petersen and Dr. Hartmut Weber. Fourteen consulted on the French edition, including Astrid-Christiane Brandt, Sebastian Dobrusskin, Olivier Masson, and Marie-Elisabeth Potier. (2.4)

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Storage of Natural History Collections: A Preventive Conservation Approach. Carolyn L. Rose, Catharine A. Hawks and Hugh H. Genoways, editors. Vol. 1. Society for the Preservation of Natural History Collections, 1995. $36 ppd. from SPNHC Treasurer, 121 Trowbridge Hall, University of Iowa, Iowa City, IA 52242-1379. Overseas air mail $46. Mastercard and Visa accepted. 448 pp. ISBN 0-9635476-1-5.

Volume 2 was published three years before this volume, and was reissued in 1995. It is called Storage of Natural History Collections: Ideas and Practical Solutions, and had (has) the same publisher and price. ISBN is 0-9635478-0-7.

This volume, v.1, has much more in common with book and paper preservation than v.2 did. Its 29 chapters are grouped under five headings: Creating and Managing Storage Facilities, Creating and Monitoring Storage Environments, Selecting and Testing Storage Equipment and Materials, Storing Archival Collections and Collection Documentation, and Funding for Collections Care. All but five of those 29 chapters are relevant to preservation of library and archival materials. Each chapter was written by one or more experts. J. Andrew Wilson, of the Smithsonian's Office of Environmental Management and Safety, wrote the chapter on fire protection, and Barbara O. Roberts wrote the chapter on emergency preparedness; Cecily Grzywacz covered air quality monitoring, and so on.

The five chapters in the section headed "Storing Archival Collections and Collection Documentation" are:

Paper Documents - Dianne van der Reyden

Historic and Contemporary Photographic Prints - Debbie Hess Norris

Film Supports: Negatives, Transparencies, Microforms, and Motion Picture Films - Douglas W. Nishimura

Video Tapes - Alan Calmes

Compact Discs and Other Digital Optical Discs - William R. Nugent

The book is well supplied with tables of information, annotated lists of addresses, tables and diagrams for identifying storage materials, and lists of references. There is a good eight-page glossary and a 17-page index that unfortunately lists as many as 50 or 60 page numbers after some terms (e.g., "color" and "deterioration"). If the subjects could have been broken down further, it would have been more considerate for the reader.

Other than that, the book was done with skill and loving care. It is well designed, easy to consult, up to date, and accurate in every important respect (at least in the section that covers record materials). Doug Nishimura and Debbie Hess Norris did a good job of explaining some fairly technical information clearly. William R. Nugent's chapter on optical discs was quite technical and full of information, though one wonders whether the people who care for natural history collections need all that detail.

Staff in natural history collections here and abroad should find this book quite useful, especially for reference. It could almost serve as a textbook, because of its broad scope and wealth of useful information. (2.7)

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Preserving Scientific Data on Our Physical Universe: A New Strategy for Archiving the Nation's Scientific Information Resources, by the National Research Council's Steering Committee for the Study on the Long-Term Retention of Selected Scientific and Technical Records of the Federal Government. $25 + postage from the National Academy Press, Washington, DC (202/334-3313; 800/624-6242) 1995. 67 pp.

The Steering Committee's working papers, covering five fields of physical science, are published separately in Study on the Long-term Retention of Selected Scientific and Technical Records of the Federal Government: Working Papers (National Academy Press, Washington, DC, 1995).

Since almost all scientific data are now acquired, stored, and distributed electronically, the committee devoted most of its attention to data stored on electronic media. The reasons given for preserving scientific observations are compelling:

Many are records of natural events that will never be repeated, e.g. a supernova or a volcanic eruption.

The further back a record goes, the easier it will be to predict future occurrence and trends, e.g. the ozone hole over the South Pole.

A data record may have more than one life, as new methods of analysis become accepted and new theories call for a second look at the data on which the old ones were based.

The last reason involves the cost of preservation, and is so well put that it is quoted here:

"The substantial investments made to acquire data records justify their preservation. The cost of preservation will almost always be small in comparison with the cost of observation. Because we cannot predict which data will yield the most scientific benefit in years ahead, the data we discard today may be the data that would have been invaluable tomorrow."

There are obstacles: No scientific discipline attaches a high or even moderate priority to data management and preservation; new research projects tend to get much more attention than the handling of data from old ones. Sometimes the data are saved, but not migrated to new storage media or identified and cataloged. Sometimes they are lost, like the original record of the Van Allen belts. NARA is supposed to archive all types of federal electronic records, but it has a budget that was only $2.4 million in 1994, and it does not have any staff scientists capable of appraising scientific research records, or any prospect of being able to hire one.

The Committee proposes a strategy for handling the problem, and makes recommendations that are not far different from those made by the Task Force on Archiving of Digital Information, whose report is summarized on the last page of the November issue of the Abbey Newsletter. Other countries are establishing committees that will probably make, or have already made, similar recommendations.

The Committee's main recommendation is to establish a National Scientific Information Resource Federation, which would be part of the National Information Infrastructure, made up of scientific and technical data centers and archives. (2.61)

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"Appraising the Records of Modern Science and Technology," by Helen Samuels. Janus 1995.2, p. 8-19. The journal Janus is an archival review publication that appears twice a year and is distributed free to all members of the ICA. This issue has in it six articles on the records of science and technology, including their preservation, so it serves as a kind of supplementary reading for the NRC's Steering Committee report. (2.61)

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"Summary Proceedings of the Liège Meeting: Archiving the Records of Contemporary Science." ICA/SUV Communiqué, Newsletter of the Provisional Section of University and Research Institution Archives, 2 #1, July 1996, p. 2-4.

In May 1996, the subgroups of two international organizations met at Liège to discuss their common concerns: documenting [collecting records] of contemporary science, and contemporary [electronic] records creation and recordkeeping. Some of the key themes of the meeting were:

The meeting expressed concern that the problem of integrity, authenticity and credibility of electronic records is large but not well understood, and that research is needed before strategies can be developed to deal with it. Working groups were set up to develop strategies for individual archives, national scientific communities and the international science archives community. One of their first steps will be to raise awareness.

For more information, contact Marjorie Barritt, Bentley Historical Library, University of Michigan, 1150 Beal, Ann Arbor, MI 49109-2113 (e-mail: margb@umich.edu). (2.61)

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Characterizing Sources of Indoor Air Pollution and Related Sink Effects. (STP 1287) ASTM, W. Conshohocken, PA, 1996. 406 pp. (There is no ISBN #.) $99; member price $89. Order from ASTM Customer Service, 610/832-9585.

This features state-of-the-art information on indoor air pollution sources and their potential interactions with indoor sinks, from leading experts in the field. Topics include: design, construction, characterization, and operation of test chambers/facilities; testing protocols for determining emission factors and sink adsorption/desorption rates; and models for predicting source and sink behavior. (2C1.2)

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"Comments from a Conservator on Climate Control," by Barbara Applebaum. WAAC Newsletter v.18 #3, Sept. 1996. (Appeared originally on the Conservation DistList in August.) This is a good clear summary of conservators' objections to the Smithsonian scientists' claim that museums could save millions on environmental control if environmental standards were greatly relaxed. The author discusses the relationship between science and conservation, the differences between the professional responsibilities of conservators and scientists, and the chasm between research data and recommendations for collections management.

All museums contain a wide variety of microclimates, planned and unplanned, she says; part of collection management involves storage or display of artifacts in the microclimate that is best suited to their needs, as far as possible. Many other factors besides the species of wood used for a coated wood artifact will influence how it reacts to its environment, although the Smithsonian scientists did not take them into account: the orientation and position of the wood on the tree, the number and relative grain orientation of joined pieces, the elasticity, permeability and adhesion of the coating(s) and the number and orientation of surfaces to which it has been applied, among others. The relative value of an artifact determines the degree of care that is given to it.

Appelbaum concludes by saying that the arithmetic that went into the money savings figure has not been published, and the scientists have not made clear the connection between their data and their conclusion. Furthermore, she feels that conservators see it as irresponsible to tempt museum administrators with multimillion dollar savings based on the idea that the field of conservation has been mistaken about environmental control. Savings can be had in some cases, and environmental control can be improved, but no data have been offered yet that support the recommended changes in collection management.

In the same section of that issue of the WAAC Newsletter is a two-page article by the four Smithsonian scientists, reviewing some stress-strain data for hide glue and one kind of wood, and offering some general reasons why closer control of RH fluctuations will necessarily cost more than a system which is allowed to vary. There is also an article by Steve Weintraub, "Revisiting the RH Battlefield: Analysis of Risk and Cost," which takes a middle position. The last item in this section of the newsletter is a formal announcement that the Smithsonian is cosponsoring a conference next fall at which the issues will be discussed. (2C1.7)

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SPEC Kit 214, Digitizing Technologies for Preservation, compiled by L. Suzanne Kellerman and Rebecca Wilson. ARL Office of Management Services, Systems and Procedures Exchange Center, 1996. $25 + $6 shipping & handling for members; $40 + $6 S&H nonmembers. Call 202/296-2296; or consult ARL's online Publications Catalog for ordering information: http://www.arl.org/pubscat/ and http://www.arl.org/spec/.

ARL's bimonthly newsletter describes the SPEC Kit thus:

"[It] documents the tremendous variety of digital preservation projects underway and describes them in terms of size, scope, and types of materials being digitized, as well as hardware and software chosen for each project. Detailed information is included on current project status; materials selection; indexing and bibliographic control; and staffing and production. More than half of the reporting libraries began by implementing pilot projects as a means of gaining familiarity with the opportunities and advantages that digital technologies offer. The cumulative experience gained from these projects will inform future endeavors."

(arl=Association of Research Libraries.) (2E3)

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Disaster Consultants is LAPNet's select, nationwide listing of individuals who can be contacted for advice after a disaster. They are listed by specialty, e.g., mold or earthquake recovery. (lapnet=Los Angeles Preservation Network.)

LAPNet's List of Disaster Supplies and Suppliers is also nationwide, but is biased toward those that are close to Los Angeles. Both publications are available from LAPNet, for $20 and $35 respectively. For more information and an order form, contact Katharine Donahue, LAPNet Treasurer, c/o UCLA Biomedical Library, PO Box 951798, Los Angeles, CA 90095-1798. (From a notice on the Cons DistList in September.) (2F3)

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Redefining Disasters: A Decade of Counter-Disaster Planning. Proceedings, 20-22 September 1995, State Library of New South Wales, Sydney, Australia. Rev. ed., 1996. Published by the State Library of New South Wales (+61 2 230-1679, fax +61 2 233-3192). ISBN 0-7310-6602-2. 260 pp. 95 Australian dollars.

There are 30 papers in this volume, which focuses on centralized disaster plans for national libraries or programs serving large areas like states, in five countries, not including the U.S. Some of the papers are a little rough, since they were not edited before publication. Jeavons Baillie's paper, the first one in the book, is one of these, but it is instructive nevertheless. He describes the events they experienced or avoided by careful planning at the new building of the National Library of New Zealand since 1987, when they moved in. One of the measures they took was to install canopies with gutters over all stacks, to keep water from leaks or malfunctioning equipment off of the books.

Grant Collins' paper, "Salvage of Fire-Damaged Collections," describes the methods he used to salvage books and records damaged by soot and water, and illustrates the damage in four photographs. He used Dry Chem sponges; a private company treated the second collection with ozone, which Collins has reservations about.

Mark Fischer of BMS Catastrophe Australia, Melbourne, provided significant information that is not easy to find through the usual channels. His paper was printed (and perhaps given) in outline form, mainly as brief instructions on what to do, and concluded with a list of questions the disaster recovery coordinator will need to have answers to when they get there.

B.M. Lee's paper was on "Fire Protection for Libraries; A Technology Update." He discusses aspirating smoke detectors; automatic sprinklers and the features recently introduced for them; the sprinkler performance record of the last century; and replacements for halon, including Inergen (a breathable inert gas, used together with only about 60% of the usual amount of oxygen-enough for people, but not enough to support fire).

Recommended. (2F3)

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Managing a Mold Invasion: Guidelines for Disaster Response. (At head of title: Mold.) Technical Series No. 1. 1996 update. $3.50 per copy prepaid from Conservation Center for Art and Historic Artifacts or CCAHA, 264 South 23rd St., Philadelphia, PA 19103 (For orders of more than ten copies, contact CCAHA at 215/545-0613, fax 215/735-9313). 6 pp.

This guide is unusual for its emphasis on health concerns, which have been neglected in the United States until recently. Its advice is sound, and it presents a full range of options and actions, from making sure that what is on the books is really mold in the first place, to follow-up and preventive actions, e.g., regular dusting. There is a well-chosen bibliography and a list of seven commercial services for mold disaster recovery, all of which are nationwide. (2H1.1)

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"The Feasibility of Using Modified Atmospheres to Control Insect Pests in Museums," by Michael K. Rust, Vinod Daniel, James R. Druzik and Frank D. Preusser. Restaurator v.17 #1, 1996, 43-60.

All life stages of twelve insect pests found in museums were exterminated at 25.5°C and 55% RH, in a nitrogen atmosphere, in order to find the time required for 100% kill. This ranged from three hours for the adult firebrat to 192 hours for the eggs of cigarette beetles. The oxygen level was kept below 0.1% with the aid of tanks of dry nitrogen and two packets of Z-1000 Ageless in each chamber. Although higher temperatures would have speeded the process, the temperature of 25.5°C was not exceeded because some museum artifacts are harmed by excess heat.

This can be called a definitive study, because it starts with a review of the literature, involves all life stages of a large number of insects (who were observed by a large number of scientists, totaling seven or eight counting the ones mentioned in the acknowledgements), addresses all major questions from the field, and concludes with 24 well-chosen references. (2H3.4)

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"Preserving our Documentary Heritage: The Case for Permanent Paper," prepared for the IFLA Section on Conservation by Robert W. Frase, with the assistance of Jean I. Whiffin. IFLA Section on Conservation, 1996. 12 pp. (No ISBN.)

The sections of this booklet are headed:

Attention: Paper Manufacturers and Distributors, Printers, Publishers

What is Permanent Paper? (Here it says, "'Permanent' refers to the paper's chemical and physical properties, which increase longevity but do not prevent recycling"-a good point, because some people are confused about this.)

What is the International Standard?

Why use Permanent Paper? (Six kinds of beneficiaries are named, in addition to libraries and archives, along with the reason that permanent paper is a benefit to them: authors, researchers, scholars, publishers and printers, governments, and citizens.)

Is Permanent Paper more Expensive?

Is Permanent Paper Environmentally Sound?

Why not use Recycled Paper for New Books? (The pros and cons are given.)

Is Permanent Paper Readily Available?

How much Permanent Paper is Actually Being Used? (Figures are given from the National Library of Medicine surveys in 1987 and 1991, and the 1993-94 survey of European publishers by the European Foundation for Library Cooperation. It would have been appropriate to give figures too from the numerous surveys of incoming library books over the last 13 years, because they show a clear trend not only in the U.S. but in other countries; but a complete summary of survey results has never appeared in print.)

Librarians Take up the Challenge

There is a brief bibliography, and two sources of further information: 1) The Chair, Section on Conservation, International Federation of Library Associations and Institutions, P.O.B. 95312, 2509 CH The Hague, Netherlands; and 2) The Director, International Centre, IFLA Core Programme on Preservation and Conservation, Bibliothèque de France, 2 rue Vivienne, 75084 Paris Cedex 02, France.

There are plans to translate this booklet into the languages of all the members of the Standing Committee of the Section on Preservation, and to distribute it in their countries-a good plan, because this booklet gives unusually careful and accurate coverage to a subject that few authors can handle well. (3A9.4)

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"Aspects of Chemical Research in Conservation: The Deterioration Process," by Robert L. Feller. Journal of the Amer. Inst. for Conservation, 33, 1994, 91-99.

This was one of seven papers presented at AIC's update session on conservation research and technical studies in 1993. To help explain why conservation research sometimes appears to lack relevance to conservation practice, Feller describes several patterns of deterioration and shows why it has been necessary to look for and investigate the subtle signs of chemical change in materials that may appear to be quite stable, so that preventive measures or treatment can be started before physical changes accelerate.

Some materials deteriorate at the same rate from the beginning; some appear stable for the first few years or decades (the "induction time"), then decay rapidly; some deteriorate more rapidly at the beginning, then slow down gradually; and others have a rate of deterioration that changes constantly throughout their life. Other patterns exist too. High density polyethylene and other plastics and coatings sometimes grow stronger during outdoor exposure before they start to deteriorate, because of cross-linking or the loss of volatile components.

The decision to treat an artifact usually involves an estimate of the speed at which it is deteriorating, and its probable lifespan. The conservator who is aware of the different aging patterns of different materials is less likely to make optimistic assumptions about an apparently stable object (such as a cellulose acetate film, which has an induction time of 30 or 40 years).

Because conservation scientists have investigated the chemical changes going on during the induction time, they can sometimes recommend action that will postpone the time of rapid deterioration. The research that made these actions possible may not have seemed very relevant to conservation at the time, because it focussed on basic mechanisms, but it pays off later. Each material gives its own clues to those who know what to look for, such as an increase in weight, a change in the infrared spectra, production of odors or exudations, or loss of moisture. (3B1.21)

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"PhD Degree for IPC Sponsored Student," by Derek Priest. Paper Conservation News, #79, Sept. 1996, p. 23.

A graduate student at the Department of Paper Science at UMIST (University of Manchester Institute of Science and Technology) has been working under Derek Priest during recent years to develop a nondestructive method of testing the strength of old paper, using ultrasonics to measure the modulus of elasticity. It turned out that modulus of elasticity does not vary much with age, so they had to give it up. The student did get his Ph.D., though.

Now they are looking at another kind of test that gives an excellent correlation with the deterioration that occurs in the aging oven. Although Derek Priest has now retired, he hopes to pursue this approach. (3B1.22)

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"Degradation of Cellulose at the Wet/Dry Interface. I. The Effect of Some Conservation Treatments on Brown Lines," by Anne-Laurence Dupont. Restaurator v.17 #1, 1996, 1-21.

What paper conservators call tidelines, the brown lines that form in paper and cloth along the edge of a previously wet area, were investigated by the dye and textile industries during the 30 years following 1934. When better drying methods were found to control the problem, the research came to an end or greatly diminished. The author builds on that work, however, to address problems that have concerned paper and textile conservators, for example: Are tidelines always apparent to the observer? How can they be removed? What are the minimum necessary conditions for their formation? What is the best way of detecting faint lines? What are they composed of? How are the lines related to foxing and to browning of leaf margins in books? Do tidelines form on the suction table?

Her experiments and review of the literature provided some answers. Briefly, they were: No, tidelines are not always visible; some come out only after aging. Sometimes they can be washed out, provided they are washed with the same liquid that formed them (e.g., alcohol); sometimes they can be made less apparent with sodium borohydride. Any wet/dry interface, even a brief exposure, may be a potential cause of degradation. The lines are best detected under UV light, rather than methylene blue. Aging darkened the brown compounds in the line and made them insoluble; they consist of cleaved compounds, as well as of oxidized cellulose with new end-groups. The author plans to publish her report on the composition of the degradation products in a future issue of the Restaurator. Foxing, darkening of page margins and tidelines may all be caused by fluctuations in moisture content of a part of the paper. Yes, tidelines do form on the suction table, even if they are not always immediately visible. Paper must be dried very quickly after being treated on the suction table. (3B1.25)

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"Effect of Various Deacidification Solutions on the Stability of Cellulose Pulps," by Jana Kolar and Gabrijela Novak. Restaurator v.17 #1, 1996, 25-31.

This is the first report in a project undertaken to compare the effects of calcium and magnesium compounds on paper. After 50 years of use, opinion still differs on which is better at stabilizing paper.

Handsheets were made of three pulps, all of them very close to pH 6.4 to start with. They were deacidified with aqueous calcium hydroxide and magnesium bicarbonate solutions by immersing them for 30 minutes, and with a nonaqueous solution of carbonated magnesium methoxide for 10 minutes, then dried and aged for 28 days at 80°C and 65% RH. Afterward, the handsheets were reduced for 24 hours with sodium borohydride and viscosity was measured to indicate degradation. Surface pH measurements were taken with a flat-head electrode and brightness was measured.

Results: All three handsheets took up much more Mg than Ca, in terms of mmol/kg paper. Those treated with Mg had a higher pH (9.9 as opposed to 8.5) after aging, as one might expect, because the deacidification solutions for magnesium were four times stronger than those for calcium (0.04 M vs. 0.01 M). Intrinsic viscosity was much higher for two of the calcium hydroxide treated papers. The sulphate (kraft) papers, however, showed little variation in viscosity, pH or brightness as a result of treatment with any of the solutions.

Stability was increased to the greatest extent with calcium hydroxide, and least with magnesium bicarbonate. (This may not be a fair comparison, because the solutions were not of equal strength, and did not have the same pH. Some papers may be damaged by a pH of 9.9, regardless of the alkaline solution used.) (3B2.4)

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