Storage: Slides should be maintained in a constant environment which is cool, dark, dust-free and held at a moderate relative humidity. Obviously, they cannot be maintained in any filing or shelving system open to ambient environmental conditions. Unless there is a very good reason for doing so, slide collections should not be open for direct browsing by patrons because constant handling is what damages slides. They should be maintained in some sort of closely monitored or closed filing system accessible only by trained staff. There are a number of means of physically storing slides which have gained popularity and wide use. Slides may be stored in cabinets which consist of shallow drawers, often with translucent bottoms and defined slots for each slide. Slides are placed flat in the drawer with any identifying labels facing up. Slides can be viewed by placing a light source beneath the open drawer. One advantage of this storage method is that it makes it easy to browse the collection in place and to locate individual slides rapidly. Another advantage is that it makes shifting the slide collection relatively easy. The principal disadvantage is that slides which are lain flat accumulate dust relatively rapidly if the collection is used even moderately. Slides can be stored in translucent plastic sheets with transparent plastic pockets designed specifically to accommodate them. These are generally designed either to be housed in ring binders or in hanging file drawers. Significant advantages to storage in such plastic sheet products are that they are easily transportable and offer an added measure of protection for the slides when in the pockets. The sheets can be handled and viewed by patrons without risk of damage to the slides. Significant disadvantages are that the pockets are relatively expensive, they make shifting the collection difficult, and they generate static electricity, a significant attractor of dust, when slides, especially those in plastic mountings, are removed. Metal cases with slots or bins designed to accommodate transparencies, called slide cases, can be used to organize slides, as well. They come in a variety of sizes and styles. Some are designed to be stackable. Many are lockable. The advantages to slide cases are that they are relatively portable, they are compact, they are easy to organize and they are relatively secure. The principal disadvantage of slide cases is that the slides cannot be viewed without being removed from the case and placed on a light table, in a viewer or in a projector. For compact, secure, long-term storage, however, slide cases are clearly superior to most other storage devices. Electronic storage is becoming an increasingly popular means of managing images, and, therefore, the information, slides and other photographic media contain. A number of sophisticated software systems have been developed at universities and corporations which have substantial photographic collections, now in the process of conversion to electronic images, in order to manage these new "virtual collections." There are also a number of commercially available programs for use with microcomputers which have been designed to manage image collections (see Appendix). The principal advantages of electronic storage of images are that it completely eliminates physical damage and degradation, that it can make images accessible electronically even from remote locations and that it makes images available for other potential computer applications. The principal disadvantages to electronic storage of images are that it requires a very significant investment in computer equipment and additional staff to scan the images, that it requires staff and patron training in the use of software and that it may cause the loss of some of the detail, color and depth of the original photographic image. At present, electronic storage of photographic images is clearly out of the question for small facilities because of the costs involved. Although clearly related, it is also somewhat out of the scope of a discussion of the library issues associated with physical collections.

Handling: Proper handling is paramount to maintaining a slide collection. Fingerprints are the principal destroyers of slides. Some have suggested that they should be handled only by the edges and with gloved hands but gloves are clumsy, can cause accidents, and may leave lint on the film. Care in handling, including making sure it is infrequent and brief, is enough. Special care needs to be taken not to contact the film surface in any way. Electrostatic deposition of dust and exposure to very bright light during normal projection is also very damaging to slides. This kind of damage is an unavoidable consequence of use but it can be minimized if projection equipment is adequately maintained and patrons are instructed in its proper use. Projection may not be necessary in order to view slides. There are many styles of light table and hand-held viewer which can be used as an alternative to projection if the slides are being viewed by an individual patron rather than a group.

Cataloging: The Anglo-American Cataloguing Rules 1988 second revised edition (AACR2R) governs the description of photographic slides. They are defined in the glossary in Appendix D as, "Transparent material on which there is a two-dimensional image, usually held in a mount, and designed for use in a projector or viewer." Rule 1.1C1 proscribes the use of the general material designation (GMD) slide for photographic slides and transparencies. The GMD is contained within square brackets in subfield h of field 245 of the standard MARC record, e.g.; 245 10 a Winged victory h [slide] Rule 8.5B1 proscribes the use of the special material designation (SMD) slide to designate 2 X 2 photographic transparencies and to distinguish them from sheet transparencies designed for use as overlays. The SMD is contained within subfield a of field 300 of the standard MARC record. It is preceded by the number of physical artifacts, e.g.; 300 a 1 slide : b col. . Rule 8.5C2 proscribes the use of the designators col. and b&w, respectively, to indicate color or black and white slides. Color designators are placed in subfield b of field 300 in the standard MARC record following the extent of the item and preceded by a space-colon- space (see example above). Rule 8.5D5 stipulates that dimensions are not to be specified if the slides are of the standard 2 X 2 inch (5 X 5 cm.) size. Otherwise, the dimensions would be contained in subfield c of field 300 of the standard MARC record format (see example above). In 1986 the Library of Congress proposed genre and physical characteristic headings to include information on these characteristics in catalog records to graphic works, including photographic slides. A thesaurus of graphic materials genre and physical characteristics subject heading (GMGPC) to be used to enhance access to visual collections was developed. The terms are applicable to all graphic forms, including slides. Proposed rules and guidelines for assigning GMGPC subject headings to catalog records in subfield a of MARC fields 655 and 755 were developed. The Library of Congress assigned the code "gmgpc" to the thesaurus and required that the code be entered in subfield 2 of MARC fields 655 and 755, e.g.; 655 -7 a Landscape prints z Germany y 1858. 2 gmgpc 755 a Chromolithographs z Germany y 1858. 2 gmgpc Rule 8.0B indicates that the chief source of information (CSI) for slides is the slide itself, which consists of both the image contained on the film or any labels permanently affixed to the front and back of the mounting. The chief source of information for a collection of slides is the slides, themselves, as above, and any labels permanently affixed to the container if it is an integral part of the collection. Clearly, if there is no labeling, the images, themselves, are the chief source of information. A slide collection can be cataloged as the collection or as the individual slides. Generally, individual slides are not cataloged because of the level of detail and specificity required to adequately describe them. Most libraries which house significant slide collections either catalog them in the aggregate as collections or use alternate, locally designed and developed cataloging and classification schemes to deal with them, outside of AACR2R and MARC.

Classification and Indexing: Slides are not characteristically classified using general classification schemes. The reason for this is that the information contained in the images is almost always too specific to be accommodated by general classification schemes. The purpose of general classification schemes, after all, is "the orderly distribution of the universe into groups of main subjects or classes or concepts." Several general classification schemes for slide collections, as alternatives to schemes like Dewey and LC, have been proposed, one or two of them very silly, but none has gained wide use. Most libraries which have extensive slide collections have developed their own classification schemes to accommodate the level of detail which is required. Classification schemes for slides of natural objects generally follow existing classification schemes for the branch of science represented. It would not be unusual, for example, for a collection of slides of living things to be organized according to standard accepted Linnean taxonomy. Slide collections classified using monothetic hierarchies like the Linnean taxonomic system are self- indexing and self-organizing. The exact nature of the thing pictured is the basis for the classification and the key to location in the collection. In the arts things can become much more complicated because significant interpretation may be involved in classification. Some focus on exactly what is pictured. Others focus on themes in the image. And still others focus on layers of representation. A slide of Picasso's painting Guernica, for example, might be described in terms of the actual objects portrayed without reference to the political or social issues involved. It might be described in terms of the anti-war themes it portrays. It might also be described in terms of the relationship of the elements to one another and the layers of meaning within each context portrayed. Such complicated analyses have resulted in the development of extremely complex and detailed faceted classification schemes at some libraries. Whatever classification scheme is used it must be suited to the needs of the patron population it is designed to serve, it must be logical and consistent and it must facilitate the physical organization of the collection. The whole object of the classification scheme is, after all, to provide patrons easy access to the images. Locally developed systems have the advantage that they can focus on the specific needs of the patron population. Whatever is done needs to be thoroughly documented, especially if the system has been developed locally.

Processing: A number of schemes have been developed for the proper labeling and preparation of slides for addition to the collection. The general consensus is that some sort of mark should be made on the slide to indicate the proper orientation for projection. The proper orientation is upside down and backwards with the emulsion side of the film facing away from the light source. In my own slide collection I have placed a red dot on the upper right hand corner of the slide to indicate orientation. Labels bearing titles, unique identifiers, statements of responsibility, copyright, etc., can be applied to the upper and lower margins of the mount. Some place them so that they can be read easily when the slide is oriented correctly for projection. Others place them such that they can be easily read when viewed on a light table or before being placed in a viewer. The scheme adopted needs to be consistent throughout the collection and needs to accommodate the major use style of the patrons. Libraries which do not wish to or cannot modify the mounting may place slides in labeled sleeves or pouches made of various materials of varying opacity but this impedes access to the collection and is not considered desirable. Labels do add measurable thickness to slides and this can be significant in large collections. Where space is at a premium and integrity of the original mount need not be maintained, libraries may permit direct notation on the mounts as an alternative to labeling. Mounts wear out after time and are subject to damage during viewing and projection. Repairs are not generally possible or even desirable. The library should be prepared with a stock of replacement mountings and the tools and materials necessary to remount film. Plastic mounts are preferable because they are thinner and stronger than the standard paper mounts and are acid-free. Lens brushes and cloths, pressurized air and other appropriate cleaning materials should be available to clean slides before they are returned to storage after use. to the Document Pages.