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Brief Glossary of Conservation Terms

Acid free - A non-specific term that refers to papers that do not contain acids. Acids can cause paper to discolor, become inflexible, and eventually turn brittle. All conservation papers, envelopes and boxes currently acquired to store LC collections are acid free.

Alkaline bath - Used in context with documents that have been washed to remove dirt. An alkaline bath deposits an alkaline buffer (reserve) into the paper that wards off future acid deterioration that may come from the environment, materials stored in the same general area, etc.

Cellulose acetate - Used in the context of lamination (see below) it is the plastic film between which a document to be laminated is placed and which bonds with paper when heated.

Enzyme baths - Used in the context of silking, documents are placed in enzyme baths to remove residual adhesive left over from the silking process once the silk sheets have been removed.

Ethanol - An alcohol type solvent used to dissolve dirt. Typically mixed with water for washing documents.

Foxing - Small spots that appear on paper; a sign of deterioration.

Iron gall ink - An acidic, indelible ink popular from the middle ages to the mid 20th century when it was replaced by carbon ink. Made of tannin, iron sulfate, gum arabic and water, and with age turns brown.

Japanese paper- A long fiber paper that is made from the inner bark of the Kozo tree and because it is extremely strong and delicate, is used to mend paper tears.

Lamination - A now obsolete but once popular method of strengthening fragile documents by placing them between two sheets of cellulose acetate film and then between two sheets of thin transparent tissue paper and then pressing the whole package together while introducing heat. The heat causes the layers of material to bond to the original document. This was a standard practice in libraries and archives between 1930-50. It can be reversed by immersing the document in repeated solvent baths to loosen the layers. Acetone is an effective solvent for this purpose.

Lignin - unpurified wood pulp commonly found in modern newsprint and other poor quality papers. It usually turns yellow over time and especially with exposure to sun light.

Mylar - Invented in the 1960s. Mylar is the proprietary name for sheet polyester, an inert materials in which fragile documents are often stored. With the advent of Mylar, the need for lamination became obsolete.

Paste paper - Decorative papers whose colors and patterns are applied with a paste in which color is carried onto the paper.

Sections - Used in the context of book binding sections are the folded sheets of paper that make up the pages. To bind a book, one sews the pages (or sections) together thorough the folds. The sewn sections are then sewn together to form a textblock.

Silking - A now obsolete but once popular way to provide additional support for fragile or torn documents by placing a document between two thin pieces of silk adhered to the document with a thin layer of paste. This process was popular between 1900-1930. In can be reversed by washing the document in water. This releases the silk layers. Residual adhesive is removed from the document by a bath in enzymes.

Spine - the part of a book on which the title appears.

Starch paste - an extremely pure paste used to fix Japanese tissue mends. It is soluble in water making mends applied using it reversible.

Tipped in - The attachment of a loose leaf of paper by means of a thin line of paste that holds the item in place. A page that has fallen out of a book can frequently be 'tipped-in' eliminating the need for the book to be completely rebound.

Window mat - a two piece housing for works of art or documents that allows them to be safely displayed. The window piece sits on top of the document that has been mounted on the bottom or support piece. The mat is typically enclosed in a frame.

HOME - GLOSSARY - CREDITS
Sections: Newspapers & Periodicals - Manuscripts - Photographs
Prints, Posters, & Drawings - Books - Maps - Music - Sound & Film


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April 28, 2000