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APPENDIX B Glossary Acid sizing. See Sizing. Acidity. In paper, the condition that results in an acid solution when the paper is extracted with water. A detailed description is given in TAPPI test meth- ods T428 and T509. Alkaline fiRers. Mineral pigments of fillers such as calcium carbonate added to paper to neutralize acids that may form in the sheet. These fillers provide an alkaline reserve in the sheet. Alkaline sizing. See Sizing. ANSI. American National Standards Institute (a standards organization). Archival film. A photographic film that is suitable for the preservation of records having permanent value when stored under archival storage condi- tions and provided the original images are of suitable quality. Basis weight. The weight in grams per square meter, as described in TAPPI test method T410. Basis weight is also expressed as pounds of a ream of 500 sheets of a given size. The sheet sizes are not the same for all kinds of paper. Compact disk. A prerecorded 4.7-inch-diameter optical disk used to store audio data in digital form. Computer output microfilm (COMJ. Microfilm produced by a recorder that takes data directly from a computer, converts it into alphanumeric form, and records it via a camera directly onto film without any intermediate paper copy. Cotton ginning. The separation of the seed hulls and other small objects from the fibers of cotton. Cross direction. The direction in a paper or plastic web that is perpendicular to the machine or length direction. Density. The degree of opacity of a photographic film image, normally expressed in logarithmic terms. Diazo film. A type of microform in which the active ingredient is a light 94

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GLOSSAR Y 95 sensitive diazo dye. It is used mainly for duplication and is not archivally permanent. Elastic behavior. The behavior of a material that returns instantaneously to its initial form or state after the forces that caused its deformation are removed. Erasable optical disk. An optical disk onto which data may be written, erased, and rewritten. Fiber. A hollow tubular cell that gives strength and support to plant tissue. The walls of plant fibers are largely composed of cellulose. Filler. Mineral pigments such as clay, calcium carbonate, and titanium dioxide that are added to the fiber furnish of paper. Finding aid. A document listing, indices, or other description to aid in identify- ing and locating a record. Flat-bed camera. See Planetary camera. Flow camera. A camera system into which the original document is inserted and the document's continuous movement is synchronized with the film movement during exposure. Also known as a Rotary camera. Formation. A property of a sheet of paper determined by the degree of distribu- tion uniformity of the solid components with special reference to the fibers. It is usually judged by the visual appearance of the sheet when viewed by transmitted light. Free sheet. Paper free of mechanical wood pulp or other lignin-containing pulps. Furnish. The raw materials placed in a beater for making paper pulp. Hygroexpansivity. The change in dimension of paper that results from a change in the ambient relative humidity. It is commonly expressed as a percentage. Hygroscopicity. The ability to absorb water vapor from the surrounding atmos- phere. It is measured by the change in moisture content with the relative humidity of the atmosphere. Inelastic behavior. The behavior of a material that exhibits irrecoverable response to forces {compare Elastic behavior). Interleaving. The placement of a document between two sheets of polyester film. Intrinsic value. The archival term applied to permanently valuable records that are archivally acceptable only in their original physical form. Long-term film. ~ ~ ~ ~~ ~ ~ ~ ~r A photographic film that is suitable for the preservation of records for a minimum of 100 years when stored under "archival" condi- tions, provided that the original images are of suitable quality. Machine direction. The direction in a paper or plastic web that is parallel to the length direction during manufacture (compare Cross Erections. Magneto-optical recording. An erasable technique for storing data by means of an octicallv addressed magnetic medium. , , ~ Medium-term film. A photographic film that is suitable for the preservation of records for a minimum of 10 years when stored under "medium-term" conditions, provided that the original images are of suitable quality {com- pare Long-term film). Microfiche. A sheet of flat photographic film containing rows of images with an eye-legible title. Normal size is 6 x 4 in. { 148 x 105 mm).

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96 GLOSSAR Y Microfilm. v .- ~ Microforms. A term embracing both roll and flat microfilm formats. Micrographics. The miniaturization of images onto photographic film. Negative film. A photographic film in which the light and dark areas (polarity) of the film are the reverse of the original. Optical disk. A round flat storage medium on which information is stored that is read and/or written using focused light {usually a laser). Orthotropic. Having three mutually perpendicular symmetry planes: the machine, the cross-machine, and the thickness directions. Paper is an orthotropic material. Pennanence. The property of a material that resists changes in any or all of its properties with the passage of time. Permanence is affected by temperature, humidity, light, and the presence of chemical agents such as acids. It is estimated by accelerated oven-aging tests or by tests under other specified conditions of temperature, light, and humidity. Permanent paper. Paper that is usually acid-free and is made to resist the effects of aging to a greater degree than is usual in other papers. Phase change recording. A technique for storing data by means of a laser- induced. optically differentiable localized state change. Erasability is pro Photo~rachic film used in micrographics. , . . . vided if the state change is reversible. PJanetarycamera. A camera containing a flat bed on which the document to be filmed is placed and a rear-mounted central column that holds the camera head over the flat bed. Also known as a Flat-bed camera. Positive film. A photographic film in which the polarity of the film is the same as the original (compare Negative film I. Read only. An information storage medium or system from which prerecorded data may only be read and not rewritten or erased. Reduction ratio. The linear reduction achieved by microfilming expressed as a ratio of the original. The area reduction is the square of the linear reduction. Resolution. A measure of the ability of photographic film to reproduce fine lines and detail. It is expressed as the number of lines to the millimeter as measured from a test target. Rotary camera. See Flow camera. Silver halide film. Photographic film in which the li~ht-sensitive ingredient is a silver halide emulsion. lo, c, sizing. The process of adding materials to paper to render the sheet more resis- tant to penetration by liquids. Rosin, starches, and synthetic resins are used as sizing agents. Rosin is an example of an acid sizing, and alkaline sizing is achieved with synthetic sizes such as alkyl ketene dimers or alkenylsuc- cinic anhydride. Step-andI-repeat camera. ' A m~crot~cne camera of the planetary type {see Plane- tary cameraJ with a special step-and-repeat mechanism for filming frames along the rows in accordance with the desired format. This camera uses sheet or roll film 105 mm wide. TAPPI. Technical Association of the Pulp and Paper Industry {an industry stan- dards group). Vesicular film. A type of photographic film in which the image consists of tiny bubbles or vesicles in a polymer binder and is developed by heat. It is used mainly for duplication and is not considered archivally permanent.

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GLOSSARY 97 Videodisk. A prerecorded 12-tn.-diameter optical disk used to store video data in analog form. ViscoeJastic behavior. The force-deformation or stress-strain response of a material. It depends on the material, temperature at the time of Toad, rate of strain, and duration of the Toad. Write once. An information storage medium or system such that once a physi- cal data block is written it may not be erased or rewritten but only read. Food fiber. Elongated, hollow cells comprising the structural units of woody plants. The term "fiber" is botanically applicable to hardwoods only, while in softwoods such cells are properly called tracheids. Young'smo~lu~us. The ratio of force {stress) to resulting elongation {strain) of a material; a measure of stiffness.