On university campuses, investment in personal computers and high-speed local area networks provided students and faculty with the ability to access vast new sources of information via the Internet. Americans who cannot afford access to the Internet have increasingly turned to public libraries to bridge the information gap between rich and poor. Many public libraries have attempted to meet that challenge by making Internet access a top priority. As a result, libraries have extended their traditional roles of facilitating self-education and individual enrichment by providing low-cost or free computer access to online resources such as government, consumer, medical, and legal information. In 1996 fewer than 28 percent of public libraries in the United States offered their users access to the Internet. By 1999 that figure had climbed to more than 72 percent. For more information, see the subsection Intellectual Freedom in the Trends and Challenges section of this article. BFunding Beginning in the late 1980s, an economic recession in the United States led to dramatic cuts in funding for all kinds of libraries. These cuts were especially damaging to public libraries and to libraries in public schools. With their budgets severely reduced, public library systems across the country began closing many of their branches. Many communities-such as Worcester, Massachusetts, and Merced County, California-were forced to close their entire public library systems, including the central library and all of its branches. Public libraries that remained open often could not afford to update their collections with new books and magazine subscriptions. Even after the U.S. economy rebounded in the mid-1990s, public libraries continued to struggle in their efforts to meet increased public demand for information while facing rising costs for staff training, materials, and equipment. Public schools also face budget shortfalls for their libraries. For example, demand for Internet access strains most school library budgets, often at the expense of traditional library materials such as books and magazine subscriptions. The National Center for Education Statistics estimates that U.S. school library expenditures on books dropped from a peak of $478 million in 1974 to $266 million in the school year of 1992-93. Much of this reduction in expenditures on books is the result of costs associated with providing computers, Internet access, CD-ROMs, and other new technologies. Related costs include several thousands of dollars each year on staff training, computer maintenance, software upgrades, online reference subscriptions, and computer supplies such as printer paper and toner cartridges. For information about the history of funding public libraries in the United States and Canada, see the subsection United States and Canada: Public Libraries in the History of Libraries section of this article. When libraries allow users to physically handle their materials and to borrow them for periods of time, these materials inevitably are vulnerable to theft. Some experts have estimated that public libraries in the United States lose as much as 2 percent of circulated materials when users fail to return borrowed items. Some users steal library materials to illegally resell them, while others simply take the materials home for their private use and fail to return them. Libraries of all types primarily lose items not through premeditated theft, but when users openly check out materials and ignore pleas to return them. Many states have laws that allow libraries to turn users' overdue accounts over to collection agencies. Libraries that catch users stealing their materials cancel the thieves' borrowing privileges and often prosecute the thieves under the law. Libraries usually monitor their collections by tagging materials with magnetic strips. These strips will trigger alarms if users try to carry the materials through electronic gates at library exits without properly checking out the items at the circulation desk. Some libraries also limit access to valuable or popular items that they consider more likely to be stolen. For example, libraries may require users to leave an identification card with library staff members in order to read certain materials. Research libraries usually require users to read noncirculating materials only in designated reading rooms. Many libraries also install security cameras or have security officers who patrol reading rooms and stacks. Libraries have always struggled against the physical destruction of their collections. Fires, floods, earthquakes, and wars have damaged the holdings of countless libraries, destroying forever much of the recorded history of human civilization. But library materials also fall victim to slow decay caused by acid content in paper, insect infestation, improper storage or handling, and excessive heat, mildew, humidity, and air pollution. The slow decomposition of library materials is a universal problem, occurring on a massive scale in developing and industrialized countries alike. In 1990 the Association of Research Libraries estimated that in the United States as much as 25 percent of the materials in research libraries were at risk of serious decomposition. The situation is even worse in developing countries, which typically have much smaller budgets to direct toward the maintenance and preservation of library materials. To ensure that library materials remain available to present and future generations of library users, libraries engage in a variety of preservation efforts. These efforts include the conservation of original materials and the transfer of information from original materials to more durable formats. One of the greatest threats to library materials stems from the acid content of paper in books, manuscripts, and other materials. Until the mid-19th century, nearly all the paper used for written or printed materials was made from cotton or linen rags. This type of paper could last several hundred years without decomposition. Since then, however, the vast majority of paper has been made from wood pulp treated with acidic chemicals. The residual acid slowly decomposes the paper, causing it to become extremely brittle. The rate of decomposition depends on the original quality of the paper and on the environmental conditions under which the materials have been stored. Acid-based paper is especially susceptible to light, heat, humidity, and pollution, all of which accelerate the decomposition of library materials. After a period of 50 to 100 years, books made with acid-based paper decompose to the point where they can crumble with any handling at all. Libraries and archives can stop the harmful effects of acid in paper by using a deacidification process, which retards the embrittlement of paper, greatly prolonging the life span of paper-based library materials. In early deacidification efforts, library conservationists dipped highly valuable pages, one sheet at a time, into a water-based alkaline solution that neutralized the acid in the paper. Because this was an extremely time-consuming and expensive process, only the most valuable pages of library materials could be preserved. However, in 1996 the Library of Congress began implementing a mass deacidification process that can neutralize the acid of several thousand books at a time by using a gaseous mixture. The Library of Congress estimates that deacidification can prolong the life span of paper-based library materials by 250 to 300 years. Some research libraries and archives, especially at colleges and universities, preserve their highly valuable collections by storing them in specially designed facilities that strictly control the levels of light, heat, and humidity. The facilities also feature air-circulation systems that filter out damaging airborne pollutants. Access to the storage areas is often limited to trained staff members. The staff members retrieve the materials and deliver them to patrons for use in reading rooms, where proper handling procedures can be ensured. Publishers can contribute to future preservation efforts by following the guidelines of the American Library Association and other library organizations, which advise publishers to use acid-free paper when printing new books considered to have enduring value. Despite wide acceptance of the value of these guidelines, fewer than 20 percent of hardcover books in the United States are printed on acid-free paper. Even fewer paperback books are printed on acid-free paper. Aside from conserving original materials through processes such as deacidification, libraries transfer the information from some fragile materials to newer, more durable formats. For example, to preserve the information contained in newspapers, books, and other paper-based materials, libraries photographically reproduce the pages onto microfilm or microfiche, miniature transparencies that users can magnify for viewing or printing with special equipment. Microfilm and microfiche significantly increase the longevity of library content. They also enable libraries to store bulky, paper-based documents in much smaller spaces. Not only paper-based materials risk deterioration on library shelves. Similar dangers confront audio and visual library materials, such as sound recordings, photographs, films, and videotapes. For example, nitrate-based film stock was the only available format for motion-picture production until 1951, but the nitrate in this type of film causes it to decay very quickly, even in controlled settings. Today, half of the 21,000 feature-length films made in the United States before 1951 no longer exist. Many have been lost or destroyed, but a vast number have simply decomposed beyond repair. Libraries and archives preserve nitrate-based films by transferring the images to a more resilient, acetate-based film stock. They preserve other audio and visual materials in similar ways. For example, original sound recordings are preserved by transferring them from delicate and unstable wax cylinders or magnetic tapes to newer digital formats such as CD-ROMs. In addition to preserving their materials from deterioration, libraries must guard against the obsolescence of machine-readable materials-materials that are read and interpreted by machines. Many valuable documents in machine-readable materials were first recorded in formats that have now become obsolete. Machines able to play back the recordings either no longer exist or are so rare that they are not practical for use in libraries or even for storage in archives. For example, U.S. president Richard Nixon used Sony Model 800 machines to record the famous White House tapes that eventually incriminated him in the Watergate scandal of the early 1970s. Today these tape machines are obsolete, and only a few still exist to play back the original White House tapes. To allow historians, scholars, and interested citizens to hear these recordings, the National Archives and Records Administration transferred them to newer formats, such as CD-ROMs.
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