Photocopy
Photocopy technology emerged from machines developed for business purposes and was taken up by librarians to duplicate missing, scarce, and deteriorating materials. Librarians photocopy materials to replace missing pages from books and missing issues from periodicals. Photocopying on acid free paper is used to replace brittle books.
Preservation photocopy is copy made with a high-quality machine that is maintained in good enough condition to produce well-fused images (images that will not smudge or be picked up when a piece of pressure-sensitive tape is touched to the surface). The paper must be permanent/durable (acid free and buffered), and the image must be the same dimensions as the original, and on both sides of the leaf with good registration. When replicating a brittle book, most expert copiers will construct a paper frame to obscure the black lines that would otherwise show around the original page edges and that will center the image on the copy paper. Generally, the photocopy facsimile will be bound using double-fan adhesive techniques with an inside gutter margin of no less than 3.7 centimeters.
Once they are discovered after circulation, books with brittle paper are usually replaced by preservation photocopy of a purchase of a digital facsimile. If there are other copies available (for example, large sets or serials on microfilm, or reprints or new editions the can be purchased to replace the brittle original). Few guidelines have been developed for preservation photocopy beyond ensuring that the paper will last, the image is stable, and the final product replicates the original volume as closely as possible.
Photocopy machines are now available that can produce excellent black and white and color copies. A color copier can also produce a quality gray-scale image, rendering an old black and white photograph accurately. For this reason, quality photocopy is used increasingly to produce surrogate facsimile copies of original documents and photographs for readers and for exhibition. This is important when the original might be damaged through too much handling or is too light sensitive to be placed on display.
Older photocopied materials may have badly deteriorated because of unstable chemicals used in image production or poor-quality paper. Materials produced by old processes such as mimeograph and Ozalid wet process are undoubtedly faded and should be re-photocopied with modern equipment on good paper. Information on these processes may be found in the following:
• The Early Office Museum(tm), http://www.officemuseum.com/copy_machines.htm
• Kevin Laurence, “The Exciting History of Carbon Paper!” 1995, http://www.kevinlaurence.net/essays/cc.shtml
• Melbourne Museum of Printing, Glossary of Printing and Typography, http://mmop.org.au/TypoRedirect.htm