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AN EVALUATION OF THE BOOKKEEPER MASS DEACIDIFICATION PROCESS

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A Paper Conservator's Evaluation of the Bookkeeper
Deacidification Process

Wendy Bennett

The Bookkeeper deacidification process is assessed by a paper conservator. The treatment is impressive for the minimal preselection of materials, improvement in general cleanliness of the books, lack of observable color changes in all book components, lack of discernible odor, and absence of physical distortion of the book block. The presence of small clamp impressions in several of the book covers, the slight chalky feel of some of the book pages, and an increased tendency of the printing inks on coated paper to rub off slightly are the less desirable qualities of this deacidification process as it was tested in 1993. It should be noted that PTI has been continuing to develop and improve their product since the time of the test.

Introduction

This section of the report presents an evaluation of the Bookkeeper deacidification process from the point of view of a conservator. Typically, the treatment of acidic paper materials accounts for a large percentage of a paper conservatorŐs workload. Some of this time is spent in an effort to deacidify and stabilize papers damaged by the destructive process of acid degradation. This gives the paper conservator a unique perspective from which to evaluate a mass deacidification process such as Bookkeeper.

There are two main contributors to the making of an acidic paper: one is airborne pollution and the other is "inherent vice," i.e., the original materials composing the paper (chiefly lignin and alum-rosin sizing) are inherently poor quality. In addition to acidity from atmospheric pollution and the manufacturing process, acidity in paper can be the result of proximity to poor quality secondary materials such as ground wood pulp cardboard, wooden backings and cross-linked glues or pastes. Heat and moisture tend to catalyze the degradation process, i.e., unregulated temperature and humidity, a situation common in many libraries, historical societies and archives, speed up deterioration. If the acidic process is allowed to continue unchecked, originally flexible papers will readily break apart with even the most gentle handling. If paper is acidic, because of internal or external factors, conservation procedures can never completely reverse physical deterioration but can slow it down.

Paper conservators generally counter the effects of acidity in paper by raising its pH to about 8.5-9.0 by means of a final aqueous bath or aqueous spray application. Solutions of earth metal salts of calcium or magnesium such as calcium hydroxide, calcium carbonate, or magnesium carbonate are commonly chosen for the job. The alkaline reserve helps to neutralize the acidity in the paper and counters future reacidification from the storage environment.

This process is similar to what Bookkeeper is attempting to do on a mass scale, although rather than using water, the carrier fluid for the MgO is a perfluorocarbon suspension in a surfactant. The presence of the surfactant combined with the agitation process ideally allows dispersion of the MgO to all parts of the books. Because other sections of this report feature the actual mechanics (Domach) and chemistry (Whitmore) of the Bookkeeper process, this section will focus on the look, feel and smell of the treated books and note how they compare with the control samples.

Testing

Twenty-five test books were cut in half. One half of each was labeled and dipped in the Bookkeeper solution at the PTI facility. The books ranged from pulp paper pages with newsprint covers and stapled bindings to engraved plates within a gold-tooled leather cover. A brief visual description of each book can be found in Appendix C. Additionally, marker pen was applied to several books, and post-it notes and paper clips to several others, to see how these three types of materials often found in libraries and archives would perform with Bookkeeper.

A condition evaluation checklist was drawn up. Treated and untreated book halves were compared for mechanical and cosmetic differences as well as for odor, abrasion testing, and the existence of surface deposits.

Observations and Questions from Empirical Testing

Cleansing action and odor. When the data was compiled from the empirical tests, it was noticed that items showing surface grime emerged slightly cleaner from the tank. In addition, in at least four instances, the treated book half was lacking the musty odor of the untreated half which suggests that though not water-based, the Bookkeeper solution somehow physically refreshes the books. The cleansing action of the surfactant would probably account for this situation. As a result of this occurrence, questions arose for the Team. What became of the dirt that was rinsed away from these materials? How often is the Bookkeeper solution filtered and recycled? Is the solution filtered completely enough to avoid deposition of dirt on other materials? The fact that the books emerged cleaner and free of odor is interesting and reassuring for both librarians and archivists.

Post-it notes, paper clips, and marker. None of the post-it notes or paper clips showed any change in appearance between treated and untreated book halves. None of the ordinary underliner marker inks changed colors. There was a change in the ink of a blue felt tip marker applied to the text previously (not by Bookkeeper evaluators) which turned green on the test half of book. It was discovered that this marker was pH sensitive. Consequent testing revealed that the color change was common when this ink was exposed to alkaline materials, in general, and not to the Bookkeeper product, in particular. It should not be considered a problem except, possibly, for other pH sensitive pigments or inks.

High pH. Although the deleterious effect of a low pH on paper is commonly acknowledged, aside from possible changes to inks and media at pH levels past 10, the effects of too high a pH seem less clearly agreed upon and understood. Apart from concerns about media, Some1 believe that cellulosic materials might be damaged by high alkalinity (pH 9.5 and above) while others2 feel that it is not paper degradation but the possibility of color change that presents the most risk at elevated pH levels. Conservators have noted color changes to pigments, dyes, and inks at pH levels higher than 10.0 as well as deterioration of the paper supports, especially those containing ligneous wood pulp. Therefore, a critical eye was turned to the test books with regard to color change. The empirical testing revealed that none of the Bookkeeper treated materials showed any observable color change whatsoever, except for the aforementioned pH sensitive marker.

In regard to concerns about possible damage to cellulosic materials from the high pH, it was noted on visual inspection that none of the tested book papers or covers exhibited physical degradation or damage. Several questions come to mind concerning the high pH created by any deacidification process. Is pH exceeding 9.5 too high for book papers? Is the sudden change from an initial pH, possibly as low as pH 3, to one as high as pH 10 too drastic a shift? What are the long-term effects, if any, on library and archives materials from the magnesium compounds used to achieve the pH seen in the Bookkeeper process? These are questions that should be asked of any deacidification agent and that can be addressed in further studies.

Alkaline reserve. The Library of Congress requires a permanent and stable alkaline reserve meeting a minimum amount of 1.5% CaCO3 equivalent. They will also consider processes which introduce a lesser concentration of alkaline reserve provided that they offer equal protection against atmospheric pollution. However, Bookkeeper does meet the Library's minimum specifications. In sixteen out of twenty-five treated books, the physical presence of the alkaline reserve was noted by empirical testers, who characterized it as variably "gritty" or "chalky." This phenomenon was especially observed in books and book covers made of coated papers. Even though examiners did not, at any time, feel compelled to leave the testing room in order to wash hands, in retrospect, it might have been helpful to clean hands after handling a book so as to get a "fresh feel" of each subsequent book.

The presence of the alkaline reserve was subtle but nonetheless noticeable to the committee members on 64% of the books. This raises the question of whether the alkaline reserve could be adjusted slightly to retain more of the original "hand" of the paper while still meeting the LibraryŐs specifications. Aside from the aesthetic concern of how the alkaline reserve affects the feel of the paper, the Team raised issues of health and environmental safety which were referred to the EPA.

The Bookkeeper vendors stated that the MgO does not pose a health risk. PTI characterizes magnesium salts as "practically non-toxic by oral administration,"3 though they do report that acute exposure to large amounts of MgO in a particle size exceeding the one used in Bookkeeper can cause respiratory tract irritations. Karl P. Baetcke, Chief of Toxicology Branch I, Health Effects Division, EPA, states that in "...address[ing] the use of MgO...no concerns were expressed."4

Rub-off and Abrasion Testing. When a soft cotton ball was rubbed gently in a circular motion on the treated book papers, a few of these materials, particularly colored plates on coated papers, showed more rub-off of some colors of ink than seen in the corresponding control group. Furthermore, the pressing of a finger to the surface of the dark-colored plates on treated, coated paper left an impression, but the inks above the surface did not smear or show softening when in contact with bare fingers. Deciding that this development required more systematic testing, the Team took a selection of books to the Graphic Arts Technical Foundation (GATF) in Pittsburgh, PA, for further evaluation.

Review of toxicological data submitted in support of Preservation Technologies, Inc., proposal for a mass deacidification process. Five books were selected for abrasion testing. A variety was sought, including several printed on the coated paper stock that presented the most problems in initial rub-off tests. In one case, the color on the cover of a book showed posttreatment color transfer, but because the cover was too thick for placement on the testing apparatus, this book could not be tested. The books that were selected are as follows:

The Gavarti Comprehensive Abrasion Tester (ASTM D5181-91) was used to analyze the rub-off. In this test, a four-inch square sample of 20# bond paper was placed facing an identically sized sample from each of the test books. These materials were held rigidly by the machine's instrumentation while moving them rapidly up and down for twenty-five seconds. The 20# bond paper was then examined for offsetting of inks. In a few test cases, a density meter was employed to determine the relative lightness value of the abraded samples. Because the density meter was not sensitive enough, all colors registered at approximately the same value. (Black/cyan/magenta/yellow all registered approximately 1.5.) For this reason, testing of lightness values was discontinued.

In each case, the rub-off from the treated samples of coated papers was visibly darker than those of the untreated controls. Although the noncoated papers fared better, decreased rub resistance was also noted in the selected posttreatment noncoated papers. Since there is currently no way to scientifically quantify the extent of the rub-off by the Gavarti tester, it was, by visual examination alone, noted that the samples treated by the Bookkeeper process displayed approximately two to three times as much rub-off as did the controls. In addition, there was perceptible abrasion to the samples as a result of the testing that took the form of tiny striations on the surface of the paper. These interruptions to the printed surface of the paper were present in the control samples as well but were slightly more obvious in the treated samples, suggesting that the particles of magnesium oxide may have abraded the surface coating of the paper and taken some of the ink along with them. It is important to note again that no smearing of inks was observed, but rather it was the friction of the magnesium hydroxide particles against the surface coating of the paper that in all likelihood caused the rub-off. Granted, library books in general circulation will not be subjected to the strong friction of the Gavarti apparatus, but the question arose in the Team of what the long-term effects could be of more subtle actions such as page turning and photocopying? If the process seems to cause abrasion to the surface of coated book papers, is the process at all microscopically abrasive to the paper below the coating? Would there be any potential for damage to the sizings, adhesives, glues, thread, and other binding components found in library materials? It should be noted that the grittiness or chalkiness commented on previously is probably the same phenomenon causing this rub-off. Clearly, this is an area that may call for further research and testing.

Impresssions from clamp. Another posttreatment phenomenon was the appearance of small indentations visible on the corner edges of the covers of seven books. This apparently occurred because the clamps used to fasten the books to a dot-perforated grid left two thumbnail-shaped impressions on either side of the cover. Though changes such as these to the original appearance of an object are unacceptable from a conservation point of view and are grounds for complaint, the problem has been addressed in the latest version of the Bookkeeper process. Because the new development falls outside the time frame of the current report, future testers should pay attention to the possibility of impressions caused by equipment.

Summary

If chemical and physical testing reveals that the Bookkeeper process successfully and safely deacidifies books, the concerns raised here do not warrant rejection of the process. The book halves in the study that were treated by the Bookkeeper solution were impressively similar to the untreated halves in almost every way. True, some of the treated halves do feel slightly chalky, but this phenomenon seems to be the baseline for materials deacidified with magnesium compounds when used in a nonaqueous suspension. Further testing will determine if the clamp impressions and decreased rub resistance seen in test books treated in August 1993 are present in materials processed using the latest Bookkeeper technology. Since the vast majority of general circulating library materials, such as those represented by our test batch of twenty- five books, does not include rare or special collections material, the Bookkeeper process does represent a viable solution to the rapid physical deterioration plaguing most library materials today.

Some of the most pressing issues to arise from the consideration of the Bookkeeper deacidification process are those related to library and archival preservation and collection management. No deacidification process will be effective or suitable for all collection materials. Those librarians who choose to make use of mass deacidification, one of many viable choices for preserving collections, must understand the process and have realistic expectations about its capabilities and its effects. In her effort to address these issues, the rare book librarian has pointed out the need to communicate, evaluate, and to work in partnership with the process vendor to ensure the best possible outcome.

Issues to be addressed include the appropriate selection of material for treatment, the logistics of shipping and receiving, the care and handling of collections during treatment, and the examination and monitoring of treated items by libraries or archives.

Additional opportunities for cooperation and dialog among vendors, librarians, and scientists are apparent. How will libraries pay for deacidification? Should there be a coordinated effort nationally to deacidify primary resources as well as those important to local collections? What scientific issues related to deacidification remain unexamined? In what venues might materials be treated to ensure cost- effectiveness, i.e., regional centers, library binding companies, individual libraries, or archives?

The following report raises and addresses many of the issues important to librarians and archivists. It is hoped that the larger conservation and preservation communities will consider them and the others which will arise.

Mass Deacidification in the Library:
A Rare Book Librarian Considers Bookkeeper

Charlotte Tancin, M.L.S.

This report includes a rare book librarian's observations on the issues of handling and logistics, as well as on observed side effects which may suggest guidelines for selection of library materials for mass deacidification. As with any mass treatment process, Bookkeeper is recommended for circulating and research collections rather than for rare book and other special collections. Although only bound, published material was treated and evaluated in these tests, the Technical Evaluation Team recognized that archival collections would also benefit from the development of a reliable mass deacidification process. Twenty-five treated items were subjected to empirical testing for the presence of visual, tactile, and olfactory side effects resulting from processing by Bookkeeper. A checklist was developed and used for the evaluation. Many of the negative side effects seen with other treatments are not in evidence with the Bookkeeper process.

Empirical Evaluation

Beyond determining what the Bookkeeper process does to benefit paper--how, whether, and how well the treatment works according to Library specifications--the Technical Evaluation Team also tried to ascertain what the process does to paper (as well as to ink, adhesive, cover material, and other book components) and whether any discernible changes resulted. In particular, the Team wanted to respond to the concerns of the preservation and conservation fields related to specific undesirable side effects. Empirical tests were added so that Team members could look for potential problems in a variety of typical library materials.

In addition to the testing done by the Institute of Paper Science and Technology on the LC blue test books fabricated and supplied by the Library of Congress, empirical tests were also performed by the Team on another, supplemental test batch of twenty-five items which were collected from local libraries. Each of the items was cut in half. One half was treated and the other half retained as a control. The twenty- five treated halves were not subjected to laboratory testing, but instead were examined by Team members who compared them with the control halves for perceptible side effects such as color changes, physical deterioration, odor, and surface deposits. This small sample, which was representative rather than comprehensive, included materials typically found in circulating and research collections.

Observable Effects

In most cases, few perceptible side effects on treated material were observed. Test items sometimes emerged from treatment cleaner than the corresponding untreated halves. No odor was perceived after the treatment. In fact, in some cases, a musty smell, obvious in the control half, was removed by the treatment. The clamps used to hold test materials in the August 1993 tests left impressions on the covers of some of the books.

There was a chalky deposit, visible or, more commonly, palpable, observed in several cases. No color change resulted from treatment, except in the case of a pH sensitive marker, and no feathering of inks or pigments was observed. When illustrations on coated paper were rubbed with cotton balls, slight rub-off was observed in some cases. This ink did not come off on fingers, nor did it offset onto facing pages.

No effect on the call number labels and bar codes affixed to book covers in the selected library test batch was noted. There was no blistering, lift-off, or damage. This is good news from the point of view of posttreatment library processing. Treated books displayed no color change on their covers or damage to adhesives.

Following treatment, the test books exhibited no evidence of blocking, sticking, swelling, cockling, or any other distortion which would make the treatment less acceptable to librarians. From the empirical perspective, Bookkeeper is in many ways an attractive process because it eliminates undesirable side effects.

Selection

Once the efficacy of the Bookkeeper process and its relatively benign nature have been determined through laboratory and empirical testing, it is important to consider what type of collection materials are appropriate to select for mass deacidification. The potential effects of the mechanics of the treatment process on the material, as well as the effects and side effects of the deacidification process itself are factors in this decision-making.

As with any mass deacidification process, the items chosen for treatment should be limited to mainstream research or circulating collection materials. These collections, determined to be of long-term value, are good candidates for treatment before they become brittle. Many archival collections may also be appropriate for mass deacidification. However, archival materials were not tested as part of this project. Interested members of the archival community may wish to be involved in future testing.

Faced with difficult questions such as whether to concentrate on deacidifying new acquisitions or rather on those books already at risk, librarians will need to set priorities carefully based on local collection risk and use. The simplest and ideal solution would be to mass deacidify entire collections with no preselection, except perhaps for those items obviously too fragile or deteriorated to treat. Librarians should assume the presence of materials in every collection which are not appropriate for treatment. Few libraries, of course, except the Library of Congress, have the financial resources to contemplate treatment of entire collections. The rest of us will be faced with the need to set priorities among our collections.

The establishment of local guidelines will make possible the identification of materials appropriate for mass deacidification as well as of those items which should never be treated. Because there are a number of idiosyncratic issues relevant to preselection decision-making, some libraries will have few items to be deacidified, while others may invest significant time in establishing procedures to exclude materials from mass deacidification.

Special Collections. Special collections in general should not be treated in a mass process. Although little damage to materials was observed in these tests, special collections and rare, unique, or exceedingly valuable items should be assessed individually by a conservator who will be aware of potential effects of deacidification and handling as well as the special needs of those materials. The conservator can then make recommendations or perform treatments as appropriate. Items having artifactual value (that is, they have value as objects beyond their information content), warrant extra care in handling. The libraryŐs guidelines for preselection must reflect these issues. Brittle Paper Because no deacidification process can restore brittle paper, books whose paper is already embrittled are inappropriate for mass treatment. If items are fragile or deteriorated to the extent that handling would harm them, they, also, should not be sent for mass treatment.

Working with the Vendor

The librarian contemplating mass treatment will want to establish a dialogue with the vendor. Through this communication with prospective clients, the vendor can contribute to the development of selection guidelines and of a framework within which to discuss the special needs and concerns of the library. Mutual understanding will simplify procedures for both the vendor and the customer. For example, because of the necessary unpacking and repacking of books from the boxes which are used to transport the materials to and from the treatment facility, guidelines should be developed for packing and shipping. Librarians will want to ensure that there will be specifications for appropriate care and handling of the materials at the treatment facility.

PTI may wish to consider consulting with preservation experts to develop selection guidelines for treatment and for handling of materials sent for treatment once the process has been scaled up. The guidelines would address routing and handling of materials through the physical plant, the mechanical process, treatment work flow, and other issues. Such guidelines will be useful to customers who are choosing and sending collection items for treatment. They would also assist PTI staff in making decisions about items submitted for treatment which may be too fragile or damaged to treat.

Some potential issues were not addressed in the course of the testing, but could easily be explored. The physical process of immersion and mild, continuous agitation which characterizes the Bookkeeper process could dislodge or damage loose sheets or other material during treatment. However, no floating loose pages, unfolded maps, or damage to mounted plates were observed during the processing of the test batch. Only a few mounted plates and folded maps were included in the test batch. Evaluation after treatment of folded paper charts and maps in book pockets or of mounted plates and maps will indicate whether there is any damage or problem related to complete treatment.

None of the test books had pockets containing supplementary material in nonpaper formats such as microfiche, plastic overlays, or computer disks, but the growing presence of these formats presents yet another challenge. In some library collections such supplementary material is stored separately, while in others it is left in the pockets in which it was originally contained. Although not of primary importance to all collections, it will be a matter of interest for some librarians. Guidelines for treatment and handling will help highlight potentially problematic areas and create awareness for new users.

Logistics

In addition to the mechanics of the treatment process, the logistics of the Bookkeeper process are of interest to librarians. Books to be treated would be unpacked from the boxes they were shipped in, opened and individually fastened to the racks for treatment, removed from the racks after being treated and dried, and repacked for return shipment. This handling should present no problem for books in good condition from circulating and general research collections, and, in fact, would probably produce no more stress on such books than they would sustain through normal use, circulation, photocopying, and interlibrary loan.

In August 1993, the PTI personnel involved in the treatment exhibited care in the handling of the test materials. However, as the process is scaled up, training for PTI staff will become increasingly important. Training would introduce the staff to the appropriate handling of library materials, according to preservation standards. This will enable them to recognize preservation concerns which might arise in the wide range of materials that make up typical library collections. By making available staff training, seeking advice, and/or adding persons with appropriate knowledge and training to the treatment staff, PTI can minimize potential damage to the materials and alleviate any concerns of librarians.

One further matter of logistics should be mentioned. Librarians opting for mass treatment should be prepared to monitor the pH of their collections after treatment just as they monitor the results of other preservation activities. Pretreatment pH testing by the library is recommended not only to determine how much of the collection warrants treatment, but also to provide a baseline of information against which to assess and monitor treatment efficacy. After treatment, an ongoing program of random retesting is recommended to check treatment results and to monitor pH. And, as with all such collection assessments, keeping statistics is recommended to make sense of the data as well as to exploit fully its usefulness.

Conclusion

In conclusion, aside from the few effects noted in this report, little physical change in treated items was observed, making the Bookkeeper process a good potential option for deacidifying mainstream circulating and research collections. As noted above, rare books and special collections should be considered separately because the librarian must consider how treatment could affect value. The safest approach is the individual treatment of any items of artifactual value which warrant deacidification.

Books are such complex, composite objects that it would be difficult to ascertain in advance and guarantee with absolute certainty that a given book will sustain no undesirable effects from mass treatment. One can, however, get a feel for the odds, weighing positive results against potential side effects in order to make a decision. Based on examination of the limited test materials treated in August 1993, it seems likely that library materials of the type included in the test batch will sustain no damage.

Most of the following Appendices are not abvailable in the electronic version of this document:

Appendix A: Report of the Institute of Paper Science and Technology, Inc.

Appendix B: Report of the Environmental Protection Agency.

Appendix C: Description of the Twenty-Five Additional Test Books:

  1. gold-tooled leather; gilt-edged; foxing on engraved plates; interleaved foxed, acidic tissue
  2. Australia; fold-out, color-printed maps on hard-finish tissue; coated paper; yellow highlighting top/bottom on page 15
  3. plastic book jacket; paper jacket; pyroxyline-coated publishersŐ binding
  4. foil stamping on blue cover; typical size and publication date; marked with felt-tip marker and highlighter
  5. red cloth binding; coated paper; gold tooling on spine; black and white plates; signatures
  6. Eastern Europe; stapled; pulp paper; journal; rough paper cover
  7. stapled; mimeographed
  8. clear plastic cover; plastic spiral bound; plastic adhesive label on spine; photocopy
  9. large size; black and white illustrations on text paper; color plates on coated paper; spine label; coated cloth binding
  10. Gaylord pam binding; brown tinted ink; selin label; date-due pocket; book plate
  11. India; journal; green paper cover; lavender-tinted paper; plates on white coated paper; sewn binding
  12. sewn; plasticized cover; color illustrations; coated paper
  13. China; journal; poor pulp paper; colored illustrations on coated cover paper
  14. sewn; brittle; calendered; remainder of paper cover on spine; no other cover
  15. South America; adhesive binding; blue-coated paper cover; good pulp paper
  16. Jordan; stiff green paper plasticized cover; adhesive binding; calendered paper for text; black and white illustrations on coated paper
  17. paper dust cover; cloth book tape spine; paper-covered boards; plain paper
  18. bright blue cover; gold tooling on spine; colored maps on end papers
  19. red paper cover, gold tooling; deteriorating tape on spine; bar code; color illustrations on coated paper; tinted pages and nontinted newsprint; thick large book; adhesive binding
  20. Western Europe; mutilated; black cloth cover; gold stamping on spine; selin label; bar code; pulp paper; date-due pocket; stamped with red ink
  21. typical trade paperback; thick; adhesive bound; plates on coated paper
  22. badly repaired and falling apart; black cloth binding; clear adhesive tape on spine; bar code; block of plates on coated paper; maps on end papers, stamped with red ink; gold tooling on front cover is worn off
  23. thick paper back; paper cover; signatures; adhesive spine
  24. portfolio style; collection of color prints on coated paper mounted on one edge on calendered paper; boards exposed along spine; book cover is torn
  25. plastic spiral bound; hand covered with brown paper wrapper; hand written title in black ink; bar code; call number label, date due pocket; original cover has mounted color illustrations; color plates on coated paper mounted on black paper; black and white illustrations and text on coated paper; exposed boards are faded black

Appendix D: Summary of the Tests Performed:

A. Tests of process results: amount and distribution of applied particles.

  1. SEM pictures of deposited particles and uniformity of deposit on paper surfaces and interiors
  2. X-ray fluorescence spectra for semi-quantitative measure of magnesium particle location
  3. ICP/MS analysis to determine total particle deposit and uniformity of deposit (Also done on 4 library books which failed pH spot tests)
  4. Cold extraction pH
  5. Alkaline reserve
  6. "Completeness of deacidification": indicator spot tests with 0.04% chlorophenol red

B. Tests of efficacy in oven aging.

  1. MIT fold endurance
  2. Tensile properties (tensile strength, stiffness, stretch, tensile energy absorption)
  3. Internal tear resistance
  4. Zero-span tensile strength
  5. Opacity
  6. Brightness
  7. Color (L*, a*, b*)
  8. Retention of alkaline reserve
  9. Viscosity DP
  10. Hot alkali solubility

C. Tests of side effects.

  1. Measured properties above for unaged papers, treated vs. untreated
  2. "Condition evaluation"

Appendix E: Report of Preservation Technologies, Inc.

Endnotes From First Part of the Document:

1 Anne Lienardy, "Evaluation of Seven Mass Deacidification Treatments," Restaurator 15:1-25, 1994.

2 Library of Congress, Test and Evaluation of the Bookkeeper Deacidification Process in Support of the Library of Congress' Research and Development Efforts for a Mass Deacidification Process. Contracts and Logistic Service, 1993.

Endnotes from the Paper Conservator's Report:

1 Ann F. Clapp. Curatorial Care of Works of Art on Paper, 3rd edition. (New York: Nick Lyons Books, 1987), 25.

2 Chandru Shahani, Ph.D., interview by author, 17 May 1994.

3 Preservation Technologies, Inc., "Health and Environment Issues" (Unpublished report, August 1993), 2.

4 Baetcke, Karl P. Letter to Kenneth E. Harris, September 12, 1994.

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