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Glossary of Lamination Terms

Blocking
Pages that have stuck together in a block, as may happen when cellulose acetate film exudes plasticizers.

Buffered
A term describing paper or board that has been treated with an alkaline substance, such as calcium carbonate or magnesium carbonate, to create an alkaline reserve. This reserve, beyond the amount required to create a neutral pH in the paper, will continue to neutralize acids as the material is exposed to external pollutants or other sources, helping maintain an alkaline or neutral pH beyond the time of treatment.

Cellulose acetate
A plastic prepared from cotton linters (fibers left after ginning) and/or purified wood pulp. Cellulose acetate is clear, hard, and glossy, with little tear strength. Plasticizers are added to cellulose acetate to increase its flexibility. First developed in 1865, it was introduced as safety film by Eastman Kodak in 1908; the first commercial cellulose acetate, called Celanese, was manufactured in Great Britain in 1919. It was used widely for lamination from the 1930s until the early 1970s.

Deacidification
The process of removing or reducing acidity in paper or other materials. Paper is often deacidified using a mild alkali bath, which neutralizes any acid present and then remains in the fibers of the paper to act as a buffer against acidity that may develop in the future.

Delamination
The process of reversing lamination, usually through immersion in successive baths of acetone or another solvent.

Inherent vice
Potentially damaging conditions that are an intrinsic aspect of paper or other objects, such as the potential for high acidity present in papers made of wood pulp.

Interleaving
Blank neutral (non-acid) or buffered tissue or paper that is placed between document pages to separate them. Interleaving can help prevent the transfer of inks or other media to adjacent pages. Buffered interleaving can also reduce damage from the acids inherent in many papers.

Japanese tissue
Lightweight, flexible papers made from the bark of the Kozo tree. Their long fibers are delicate but strong, making them ideal for mending papers.

Laminate
The plastic film, often cellulose acetate, in which a document is enclosed through lamination.

Lamination
A general term for fusing together thin layers of different materials. In archival contexts, lamination refers specifically to the process of layering a sheet of paper with stronger materials, in order to strengthen the paper. The standard method, developed by William Barrow, used heat and pressure to fuse paper between two thin sheets of a plastic (usually cellulose acetate).

MicroChamber paper
A registered trademark for a line of lignin-free, sulfur-free archival papers that contain an alkaline reserve and an interior layer of zeolites. Available as interleaving, mat boards, containers, and the like, MicroChamber is designed to absorb airborne pollutants and off-gassed byproducts of degradation.

Mylar encapsulation
A method of protecting frequently handled papers from oil, grease, and moisture. The document is placed between two sheets of Mylar, a colorless inert sheet polyester, which are then sealed with pressure-sensitive tape or welding.

Plasticizer
A variety of chemicals added to cellulose acetate film and other plastics during manufacture in order to increase the plastics' flexibility.

Post binding
A form of loose-leaf binder, in which punched or slotted leaves are attached to two screw posts. This method, sometimes known as a transfer binding, was a popular means of re-binding volumes that had been disbound for lamination. It may leave brittle pages vulnerable to snapping at the binding.

Solubilize
To make soluble. In a conservation sense, a substance that has become susceptible to dissolving in a liquid such as water or acetone. Solubilized inks or pigments will run, bleed, or smear.

Vinegar syndrome
A vinegar- or ammonia-like odor, produced when the cellulose acetate molecule breaks down and releases (off-gasses) acetic acid. The presence of vinegar syndrome signals active and irreversible deterioration of laminated objects. Off-gassing may seriously damage other objects stored nearby.

Zeolites
A group of naturally occurring minerals that readily absorb liquids and gasses. Also known as molecular sieves, zeolites are used to trap potentially harmful off-gassing or pollutants.

 

Return to Guidelines for the Care of Works on Paper with Cellulose Acetate Lamination

 


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