How aging paper survives with its initial qualities intact or not is primarily a factor of the processing of its main component, cellulose, a very stable compound, and the other constituents—together called the furnish—added to the pulp or to the sheet. Other factors that impact aging include the micro- and macroenvironments in which book paper exists within the protected enclosure of the binding and within a controlled environment of a well-constructed and monitored space or building. Pure cellulose is nearly indestructible, being impervious to all but the most extreme wavelengths of light and all liquids except the strongest acids and bases. Microbes, pests, and fire are its most important enemies, being the usual suspects of destruction. (It is interesting that "antique" papers are portrayed in movies as having irregular and burned edges, whereas in reality this is uncommon.) By virtue of the gathering and processing of pure cellulose, humans compromise its native stability in order to make paper. Traditional eastern papermaking processes, which began more than 2000 years ago in China, have ensured that the cellulose primarily harvested from plants is damaged minimally. This care has resulted in very stable papers, a few very early examples of which are still extant. Fiske's article explores the present state of hand (and machine) papermaking in Japan as a few craftsmen endeavor to keep the industry going. Her conclusion about the future of this art and craft is not particularly hopeful, however, and nor is Frederick's about Lacandun hu'un, bark cloth, both important, centuries-old hand crafts trying to survive in the third millennium. The first European papermakers had to rely on the fiber from linen and hemp rags, ropes, sacking, etc., rather than directly from plants. Beginning in the thirteenth century, western papermakers used comparatively stronger chemicals (lime for retting) and more damaging mechanical action (stampers) to break down the woven or twisted structure of these worn-out materials into a pulp satisfactory for papermaking. As a result of these interventions, the fibers were fibrillated and shortened, and with the native hemicellulose associated with these fibers, they were swollen with water. The slow-draining qualities of this pulp (similar to eastern pulps with the addition of a formation aid) allowed the vatman time to form relatively thin sheets of paper on the mould. As Pullman and the conservators involved in the Library of Congress's Endpaper Project observed in their articles, when we look at the papers in western printed books dating before 1800, we clearly see the distinctive pattern of the antique laid and chain mould and watermarks. This clarity is due in large part to a combination of long and short, fibrillated fibers. Because of the way they were beaten, these fibers were able to coalesce with one another to form an evenly dense, homogeneous, relatively thin sheet, where the fibers conformed to the mould cover's undulating surface, accentuating its characteristics, all of which result in qualities that elude most hand papermakers today.1 The consistency of the pulp was described by LaLande (1761) as like "milk" and "butter- milk." Similarly in 1913, the English mould-making firm W. Green, Son & Waite, advised Dard Hunter that, in order to have a clear portrait watermark, "it is necessary to cut the fibres very, very short, and make the pulp as much like flour & water as possible."2 It can be argued that these sheets should exhibit a certain amount of brittleness and weakness, especially if in a dry environment, and perhaps it is the presence of the hygroscopic gelatin tub sizing that has rendered them more supple and stronger than expected. As Pullman points out, the long curing time routinely practiced by early papermakers served to acclimate paper to changes in environment, resulting in a more dimensionally stable sheet compared to today's heated or constraint-dried paper. Subsequent dampening, printing, and drying of older paper meant for books, following by smashing with a hammer and repeatedly pressings during binding, would have further "knocked the stuffing" out of these papers while leaving their aesthetic qualities intact. When describing the characteristics of any paper, there seems to be confusion about the terms grain and square. Contrary to popular opinion, paper, whether made by hand or machine, has grain direction, which is the greatest percentage of all fiber orientation aligned in one direction in a sheet. For machine-made papers, this percentage is usually between 12% and 15%; western handmade papers have less grain. If the percentage is too much greater than 15%, the fibers would be aligned in a predominate direction, and the sheet would have too little fiber intermeshing to withstand much use without the presence of a strong internal and/or external sizing agent. Unless the formation of the sheet deviates dramatically from the norm, e.g., in leaf casting, the grain direction in all handmade paper is parallel to the shorter dimension of the mould, predominately on the wire side. This is due to the flow of the pulp over the mould (or machine wire) parallel to the sides of the cover, and the duration and direction of subsequent shakes. This fiber alignment can be Account Ledger, 1829. Grain direction of page is long, or parallel to the gutter. This allows the pages to drape over while being turned and to lie flat while entries were made, an important feature for this utilitarian book. 36 HAND PAPERMAKING easily seen in papers made with different colored, long fibers; most of those on the wire side will align parallel to the short side, while those on the felt side will be more randomly oriented. Unless the fibers are highly processed (water-logged and slow-draining), all papers can be described as "square." That is, each fiber (and the sheet) expands and contracts equally, or nearly so, in both directions when wetted out. This is especially true of little- processed Japanese fibers, the sheets from which, however, do exhibit very strong grain direction. If the pulp is fast-draining or free, the hand papermaker cannot manipulate the upper layers on the mould before they coalesce or set. This is seen in fibers that are not highly fibrillated, are relatively long-fibered, and have little or no native hemicellulose, e.g., cotton. In the case of a free pulp, the felt side will look blotchy and mottled and will be more open and porous, and sheets made in such a way will likely also exhibit more grain direction, as there is no time to change the initial fiber orientation seen on the wire side. For maximum flexibility and drape in a book paper, it is ideal to impose the type forms—the format in which the pages are oriented on a sheet and printed—so that once the sheets are folded into signatures, the fold runs parallel to the grain. The grain direction of book papers in traditional folio and octavo formats, based on folding down full sheets, run parallel to the gutter, while papers in quarto and most duodecimo or twelves formats (apparently, the most popular format in nineteenthcentury books) run perpendicular. Paper printed so that the grain runs perpendicular to the fold tends to be stiff, to "stand up" when the book is read, and to buckle at the gutter (although the fold line is stronger across the grain). This stiffness, in combination with the hot glue, which penetrates into the paper at the fold, has caused much of the physical damage of paper seen at the gutter of books. Thus much of the physical damage seen in book papers has virtually nothing to do with the furnish of the pulp, except in the case of the embrittled papers made of groundwood pulp, but rather on the imposition of the printing paper decided upon by the proprietor of the printing office and the brittle glue used by the binder. In terms of chemical aging, these pre-1800 papers suffered most from the presence of alum. This compound, potassium aluminum sulfate, was ubiquitous in the paper mill. It was added to processing water to precipitate out debris, and added to the gel- atin to both make the sizing "harder" and to help preserve the warm and easily spoiled solution. The fact that a bit of alum could be added day after day to the same gelatin solution probably accounts for the increasing grayish-brown discoloration of a book's paper made in the same mill within days of each other. By the 1850s, pulping involved the use of stronger chemicals, heat, pressure, and mechanical action, all of which were brought to bear on pieces of straw, wood, or textiles in order to destroy their external structure. As a result, the protective, internal structure of the fiber was significantly broken and opened up, and this has made it far more vulnerable to deterioration processes compared to traditionally processed fibers. Once reduced to individual fibers to form a pulp, one or more compounds were added to change the characteristics of the resulting paper. These included sizing agents to internally strengthen the sheet and to render its surfaces more impervious to liquids and gaseous pollutants; coloring agents; and fillers to increase opacity, density, and to increase the weight. The infinite combinations of fiber and additives, as well as numerous environmental factors such as heat, humidity, light, and especially air pollution, all play a role in the aging of paper. Especially important for the understanding of making, using, and conserving paper is the essential relationship between it and water. The new book Paper and Water by Banik and Brückle, described in this issue, will provide those who work with paper with information leading to a deeper understanding of the role that water plays, and especially the heretofore little-understood or considered aspects of evaporation and drying. Understanding how water relates to paper will also provide us with better insight into how paper ages. Human aging comprises a number of concepts: time, beginning, birth, end, and death, but end and death hardly apply to paper. In order to recognize that paper rarely disappears in clouds of dust or corruption, the following discussion explores the different theories associated with the natural and artificial aging of paper. It lays bare the common fallacy that the results of aging in humans and paper are synonymous, and because of this misconception, well-meaning people in conservation and preservation view paper as having a foreseeable, finite life, with the result that chemical interventions, e.g., mass deacidification, have been applied in order to extend that life for another generation or so. Imprints, left to right: Boston, 1853; New York, 1864; Manchester, England, 1966 (an untrimmed leaf can be seen); and London, 1975. Examples of batch differences between signatures. These were probably not noticeable at the time of printing, but the papers have discolored differently over time. 38 HAND PAPERMAKING There are numerous references in the paper and book conservation literature, and in paper-manufacturing literature, to paper as if it is a living organism; the word death often appears. Although rarely expressed in the following terms, paper has been thought of as progressing through a variety of life stages in much the same way that humans age: birth occurs during the formation of the sheet from the fibrous pulp; growing up involves various physical transitions, e.g., cutting and folding, until it is functional and is impressed into or wetted by one or more media; early maturity is reached when it is gathered into books; middle and late age is the proportionately long period of use or storage; and ultimately, as in death, paper experiences complete disintegration. This assumption about the inevitable disintegration of paper is flawed, however, and in order to reach a commonsense approach to the conservation and preservation of individual objects and entire collections, these flaws must be revealed. Unlike human beings and many plant forms, but very much like trees, paper could theoretically exist forever. Curtis divides the living world into four forms of life: 1) bacterium, 2) the annual plant, 3) trees, and 4) animals.3 Bacteria do not age; they are immortal because they constantly divide themselves into new, identical organisms. Annual plants such as flax and cotton grow, reproduce, wither, and die according to genetically programmed aging. Trees, unlike annual plants, are not genetically programmed to die, and they grow continuously by cell division. Bristle-cone pines found in the Sierra Nevada Mountains are the oldest known living trees, and some West Coast redwoods are more than 3000 years old. Trees grow at about the same rate, regulated primarily by the environment, until they get into some type of mechanical difficulty. For example, the height of the tree may not allow sap and water to rise to the very top branches, and as a consequence, the tree begins to die. However, it retains the potential to live anew, and in fact, from the twigs and seeds of ancient dead trees have sprung new living ones. Animals are not so lucky, at least not in the present day. We begin with the division of a fertilized cell and change over time until we are born. From that moment on, some cells continue to divide while others cease to do so. The latter process accelerates to the point when the body is no longer able to cope with the overwhelming effect of the aging process, disease, or some mechanical difficulty such as a fatal accident, and inevitable death occurs. Paper, made largely of cellulose, is neither a bacterium nor an animal. It is intriguing to consider the aging differences Curtis describes as they work in cellulose derived from annual plants and that from trees. Clearly the aging properties of bast fibers from common annual plants, as well as from hemp and kozo, behave much like wood fibers processed from trees. On its own, cellulose has the potential to exist forever until some sort of external disaster, e.g., flood resulting in mold or fire, shortens its existence. The critical point here is that cellulose is often not the exclusive constituent of paper. It has been almost 200 years since chlorine-based bleaches and alum-rosin sizing were introduced to commercial papermaking. Since the early decades of the nineteenth century, cellulose has had to contend with internal components that create an acidic environment within its structure. However, an ongoing examination of thousands of books from the nineteenth century and early twentieth century reveals that the paper in the overwhelming majority of those has survived relatively well.4 This is not true, however, of all early twentieth-century book paper, some of which has the extra burden of the lignin associated with groundwood pulp. It would appear that the "lethal" combination of lignin and alum-rosin sizing found in paperbacks and other inexpensive books, as well as newspapers, typewriter copy paper, etc., has contributed to its marked embrittlement. The use of 100% groundwood pulp for news paper (as distinct from book paper) dates from the 1880s and well into the twentieth century. Without doubt, these papers are self-destructing. The answer to this problem should not have been, however, to mass deacidify such papers, but rather to strengthen them, so that those paper-borne objects can continue to be used, not only for the information they contain, but as historical objects worthy of study. For the past fifty years or so, more archivally sound chemical pulping techniques and alkaline sizing have resulted in papers that are far more closely related to the no-lignin/alum-rosin sized ones dating before 1830. This opinion about the innate longevity extant in most papers is not shared by all conservators, preservationists, librarians, curators, conservation scientists, manufacturers, and distributors, some of whom assume that within a foreseeable length of time, all paper will deteriorate to dust. A review of the conservation literature addressing the concept of aging paper revealed almost no discussion of this assumption, and it is equally difficult to find a definition of aging in this literature. Only Cunha and Cunha defined the term: "aging—the degradation of material leading to total destruction—is, among other things, the result of light and heat together with water vapor, aerosols, and polluting gases in the environment."5 Certainly aging occurs in paper, but rarely to the degree of "total destruction," an idea that is routinely confused with losses in strength, brightness, and whiteness, and increases in acidity, brittleness, and yellowness. In fact, there have been only a few recorded examples of paper literally turning into dust on its own, and those were related to the introduction of chlorine compounds to bleach fiber for the manufacture of white paper early in the nineteenth century. In 1856, Richard Herring wrote that, "within the recollection of my father, it was not at all an uncommon occurrence for a parcel of paper to become so completely perished from the circumstances of its not having been thoroughly washed after bleaching that an entire ream, composed of 480 sheets, might be as readily snapped asunder as a piece of rotten wood."6 Once this problem was resolved, paper no longer turned to dust, unless it was subjected to great stress, such as deliberate crumbling in the hands. From the lack of discussion in the conservation literature, one might assume that the concept of aging is of little concern to conservators and scientists, but this is not the case. Historically, the field has focused primarily on two aspects of aging paper: the correlation between natural aging and accelerated or artificial aging, and deterioration rate. Higginbotham states Imprint: Chicago, 1900. Groundwood-pulp paper internally sized with alum-rosin. Color of paper has changed uniformly to a reddish-brown with slightly darker edges (except the bottom) and at the gutter. Even though the page is stiff (grain short), the paper will probably survive 100 more years if carefully handled and stored appropriately. 40 HAND PAPERMAKING that the first serious questions about the aging of paper were asked at the turn of the twentieth century when the effects of acidic sizing became manifest in increasing numbers of brittle books.7 But while it was possible to measure the various properties of aging paper using non-destructive testing methods, the number of books that could be destroyed in order to make destructive (and more reliable) measurements was (and remains) limited. In the 1920s, Dr. Edwin Sutermeister, at the National Bureau of Standards (NBS), decided to research ways to accelerate the aging of paper in order to quantify changes in a number of properties using examples of commonly manufactured book papers.8 These properties included fold endurance, tensile strength, break elongation, burst strength, tear resistance, reflectance (brightness), discoloration (loss of whiteness), opacity, pH (acidity or alkalinity), and copper number (loss of polymerization due to acid hydrolysis or oxidation, the chief causes of cellulosic degradation). Sutermeister's goal was to determine the ideal artificial aging environment that would increased the rate of degradation without changing the nature of the degradation. Thus Sutermeister began a twenty-five year experiment to "create" a paper through accelerated aging that was chemically and physically identical to a naturally aged paper. Once this was discovered, Sutermeister and his colleagues hoped to draw conclusions about how old paper had aged, to predict how new paper would age, and to determine what impact aging would have on the various changes in the properties of new paper. Sutermeister placed unused, newly manufactured, uncoated papers in an oven at 100°C and 0% relative humidity (RH) for different periods of time but not exceeding 125 hours (5.2 days). Specific properties were measured for each batch aged for different numbers of hours. In dark storage, a stock of the same papers was kept as naturally aging controls. Periodically, sheets were removed from this stock, the same properties were measured as performed on the artificially aged papers, and the results were compared. In 1946, Sutermeister reported that a correlation had been found: accelerated aging for 72 hours at 100°C and 0% RH was equivalent to twentyfive years of natural aging. Sutermeister and his successors at the NBS planned to continue monitoring the natural aging process in the control papers, but unfortunately, the stock was inadvertently discarded a few years later. The result of this pivotal experiment was that scientists, conservators, and paper manufacturers finally had a standard method to artificially age paper that correlated with natural aging, quantitative methods to assess the aging process, and data to establish standards for permanent paper. Sutermeister's artificial aging criteria were later changed when the effects of heat plus humidity were shown to correlate more closely with natural aging. William J. Barrow, a document restorer at the Virginia State Library in the mid- 1900s, took the next logical step and looked at a wide range of books from old to new and from different western countries to see if some correlations could be found between the constituents or processing of paper and its natural aging characteristics.9 By 1945, Barrow concluded that the loss of properties was due primarily to acidity in paper whether made from rag or wood fibers. Barrow recommended a deacidification process that neutralized the existing acid in the paper and left behind an alkaline reserve to halt the formation of any future acid. This step did not strengthen already weak and brittle paper, however, and Barrow's answer to that problem was, unfortunately, lamination, a conservation step that now has to be reversed because of the disastrous effect the adhesive has had on paper. Resizing—the impregnation of a stable, internal adhesive into paper—has been routinely employed to provide strength, particularly to washed papers during conservation treatments, but it is not a practical method to use on book papers requiring strengthening. Paper splitting is currently undergoing a pilot project at the Library of Congress and is a fascinating alternative to sizing by providing internal strength to embrittled paper through mechanically splitting the sheet into two, inserting a buffered tissue in-between, and adhering the layers back together into a useable sheet.10 In 1975, Williams et al. stated that the aging of paper was a linear progression11 (Fig. 1). Unfortunately, the idea that paper deteriorated at a predictable rate over time and that the effects were cumulative helped reinforce the idea that all paper would eventually disintegrate in a relatively short period of time. A contrary opinion that more reflects actual natural aging was published by Feller in 1985.12 He studied the aging processes in great detail and theorized that aging was not linear, but rather an induction curve (Fig. 2). That is, when the cellulose chain begins to break down through acid hydrolysis or oxidation, the loss of physical properties is relatively rapid and the curve rises steeply for a short duration of time. The curve then levels off, and any further loss of strength or color change is relatively slow over a very long duration. Feller's conclusion is validated in countless pieces of papers found in the nation's libraries and rare book collections. Unfortunately, Feller's findings have done little to dispel the notion of a linear progression of aging and "death" of paper. The reason why it is important to make this distinction about inevitable death vs. slow, predictable and acceptable change is because of the vast resources that have been spent in researching and carrying out the mass deacidification of paper to control the so-called brittle book crisis, conclusions about which continue to be based primarily on empirical data gained largely through nondestructive testing and artificial aging rather than on the first-hand examination and qualitative analysis of aged book papers. Generally across the library preservation field, it is assumed that the older the paper, the more it requires some type of intervention, most notably deacidification. Millions of dollars are spent annually to fix books that are not broken. This does not mean that needy books are neglected in favor of unneedy books, but money and time is wasted. What is needed is some way to sensitize those people who make decisions about the preservation of books to the fact that aging paper and deterioration are not directly correlated; age is not the primary cause of drastic loss in physical properties. The fault lies in the processing of the Fig. 1 LOSS OF PROPERTIES TIME Fig. 2 LOSS OF PROPERTIES TIME Imprint: London, 1824. The paper is quite white with only minor, local staining. A good example of a quality paper that has retained its original characteristics over nearly 200 years. 42 HAND PAPERMAKING fiber, in alum-rosin sizing, and, most importantly, in the presence of large amounts of lignin.13 The same holds true for those who believe that by quantifying the properties of a piece of paper, we somehow fully describe it. Measuring the pH nondestructively may indicate the level of acidity on one of the sheet's surfaces, but can we be absolutely sure that the test is measuring the pH of the cellulose (which is naturally acidic), or instead the layer of gelatin sizing (also naturally acidic)? Again, feeling and looking at the paper and knowing, or at least making a educated guess, about its constituent parts yield far more useful clues as to the effect of aging and a predictable future without treatment than a conclusion based primarily on age or empirical data. To further illustrate how past and present generations view paper aging, let us consider paper as it might have been viewed in the premodern, modern, and postmodern world, and how these views may have impacted conservation and preservation policies. The premodern view of book paper might be that it was a useful material manufactured economically in small quantities. The idea of paper or books exhibiting built-in obsolescence was absurd. The modern view might be that paper was like any other commodity and produced in a highly mechanized, efficient, and economical manner. The notion of any aspect of papermaking being done by hand was an increasingly old-fashion one, the kind of activity reserved for dilettantes. Paper—now rife with built-in "obsolescence"— is ubiquitous, an economic social necessity in the wake of the explosion of education and commerce. In the postmodern world, the book might be seen as iconic while undergoing scrutiny at the molecular level. Over the last hundred years, there has been a gradual and enthusiastic interest in the handmade book. This new "old" book is clearly symbolic of the premodern book, but while the concept of it in the postmodern world is exciting, most papermakers have not managed to duplicate papers from the past. With very few exceptions, they exhibit an unawareness of, or worse yet a lack of interest in, the qualitative and quantitative aspects of old paper. Much of today's handmade paper is required to be archivally permanent and durable, but these very criteria work against the replication of aesthetic qualities found in old papers, including thinness, even formation, sufficient tensile and fold strength (mostly attributable to gelatin sizing), natural whiteness, a clear watermark and mould-pattern, slight translucency, and rattle. The requirements of conservators for paper that is much stronger than it has to be for the intended use has meant that all of unique qualities that make the old papers so wonderful are sacrificed to strength to some degree. If all of the characteristics of old paper are equally desirable, it seems prudent and reasonable that other solutions be found to render less-strong papers useable. While the quantitative methods for analyzing aging paper have existed for more than 100 years in the pulp and paper industry, in the conservation and preservation fields, the qualification of the characteristics of aging paper remain nebulous; decisionmakers seem to be more comfortable with a number than a feeling. An exemplary description of paper incorporating most of the senses appears in "Aesthetics and the Future of the Craft" by Timothy Barrett, perhaps our most eloquent writer on the subject of handmade paper. In the void of the plain sheet contemplated in our hands, small, subtle, and otherwise unnoticeable marks of the maker stand out. The richness of the raw material and the skill with which the papermaker prepared it may be more immediately considered. The plainness of the sheet requires us to use other senses in addition to sight to take in the piece of paper—we run our fingers over the surface, we listen to the sound it makes in our hands, we bring the surface of the sheet close to our nose and smell it. Many of the characteristics that speak of a paper's being handmade stand evident in a plain sheet's empty expanse.14 Another example that explores the worthiness of even the meanest of machinemade papers is presented in William Gass's article, "In Defense of the Book": My copy \[of Treasure Island\], which I still possess, was one of the cheapest...its coarse pages are jaundiced and brittle, yet they've outlived their manufacturer; they will outlive their reader—always comforting yet a bit sad. The pages, in fact, smell their age, their decrepitude, and the jam smear is like an ancient bruise....That book and I loved each other, and I don't mean just the text: that book, which then was new, its cover slick and shiny, its paper agleam with the tossing sea and armed, as Long John Silver was, for a fight, its binding tight as the elastic of new underwear, not slack as it is now, after many openings and closings, so many dry years....15 To Gass, there is no negative connotation between the effects of aging and his enjoyment of Treasure Island, and he feels comfort in the knowledge that the book will outlive him. If each of us spends a lot of time examining and enjoying the paper in as many books as we can lay our hands on, we, too, will find great solace in the reality that it has not only aged well, but that it will continue to age perhaps two or more times its existence to date. Imprint: London, 1827–1838. The grain direction of this plate (watermark: J. Whatman Turkey Mill 1833) runs perpendicular to the gutter. This stiffness together with the large size of the sheet, 27 x 40 inches, has resulted in the crescent-shaped dents seen here. The distortion in the center is due to the stretching of the dampened paper during the printing of the intaglio plate. Imprint: London, 1931. A twentieth-century handmade paper very similar to traditional paper of earlier centuries. The brown spots are probably due to mold growth on gelatin sizing that occurred as a result of keeping the paper damp during printing. 44 HAND PAPERMAKING Notes 1. See T. Barrett, "Early European Papers/Contemporary Conservation Papers. Report on Research Undertaken from Fall 1984 Through Fall 1987," The Paper Conservator 13 (1989): entire issue. 2. J. de LaLande, The Art of Papermaking, trans. Richard M. Atkinson (Kilmurry, Ireland: The Ashling Press, 1976), 19, 32; W. Green, Son & Waite to Dard Hunter, 25 February 1913, Dard Hunter Archives at Mountain House; quoted in C. Baker, By His Own Labor: The Biography of Dard Hunter (New Castle, Del.: Oak Knoll Press, 2000), 255. 3. H. J. Curtis, Biological Mechanisms of Aging (Springfield, Ill.: Charles C. Thomas, 1966). 4. The author is participating in an IMLS-funded grant to describe publishers' bindings—grain patterns, stamping, endpapers, edge treatment—found on approximately 2,500 American books ranging from 1815 through 1930. The information from this survey, including scans of covers, spines, and decorative endpapers, will be available on line beginning early in 2005. While describing the exteriors of these books, the author is also examining the text papers to gain more information about their aging and qualitative characteristics. 5. G. M. Cunha and D. G. Cunha, Conservation of Library Materials: A Manual and Bibliography on the Care, Repair and Restoration of Library Materials, 2 vols. (Metuchen, N.J.: Scarecrow Press, 1971), I:360. 6. Quoted in V. M. Clapp, "The Story of Permanent/Durable Book-Paper, 1115–1970," Scholarly Publishing, 2, no. 2 (1971): 120. 7. B. B. Higginbotham, "The ‘Brittle Books Problem': A Turn-of-the-Century Perspective," Libraries & Culture, 25, no. 4 (1990): 495–512. 8. R. B. Hobbs, "Estimating the Life Expectancy of Book Papers," in Permanent/Durable Book Paper: Summary of a Conference Held in Washington, D.C., September 16, 1960, 47–53 (Richmond: The Virginia State Library, 1960). 9. See W. J. Barrow, Deterioration of Book Stock, Causes and Remedies; Two Studies on the Permanence of Book Paper (Richmond: Virginia State Library, 1959); D. D. Roberson, "Permanence/ Durability and Preservation Research at the Barrow Laboratory, in J. Williams, ed., Preservation of Paper and Textiles of Historic and Artistic Value II, 43–55 (Washington: American Chemical Society, 1981). 10.See E. Eusman, C. Connelly Ryan, and J. Baldwin, "Investigating a Mechanized Mass Treatment for Research Collections: The 2002–2004 Paper-Strengthening Pilot Program at the Library of Congress, AIC News, 29, no. 3 (May 2004): 1, 3–4, 6; I. Brückle and J. Dambrogio, "Paper Splitting: History and Modern Technology," Journal of the American Institute for Conservation, 39, no. 3 (Fall/Winter 2000): 295–325. 11.G. M. Cunha and D. G. Cunha, Library and Archives Conservation: 1980s and Beyond, 2 vols. (Metuchen, N.J.: Scarecrow Press, 1983). 12.R. L. Feller, "Three Fundamental Aspects of Cellulose Deterioration," Art and Archaeology Technical Abstracts, 22, no. 1 (1985): 277–354. 13.It should be noted that all minimally processed bast fibers contain lignin, which may account for their slight yellowing; its presence in very small quantities, however, should not cause any concern. 14.T. Barrett, "Aesthetics and the Future of the Craft," Hand Papermaking, 11, no. 2 (Winter 1996): 14. 15.W. H. Gass, "In Defense of the Book," Harper's Magazine 299, no. 1794 (November 1999): 46–47