Some items which require protection, but whose value or structure prohibits the use of invasive conservation techniques, may be encapsulated. Encapsulation involves the sealing of individual sheets of paper between sheets of clear polyester. It is the standard treatment for maps, manuscript material, prints, and fragile or brittle single sheets.
This treatment is generally limited to Special Collections items.
At the University of Florida Libraries we use a Minter Ultrasonic Welder, model OT, purchased in 1987.
The welder should be cleaned and recalibrated monthly, or whenever a large run of material needs to be done, and/or the machine has been unused for a while.
There are two types of polyester recommended for conservation. They came in a variety of thicknesses. with 2-5 mil being the most frequently used. They are:
The candidates for encapsulation should be printed, typed or manuscript material. Artwork may not consist of friable media such as charcoal, chalk or pastel. Such media is loosened by the electrostatic charge of the polyester. Material should not be overly thick or adhered to board or have a rough, three dimensional surface.
Several things have to be taken into account before encapsulation. They include:
Will they be:
Examine the item to be encapsulated for any damage and assess any treatment that needs to be perfomed before encapsulation. Treatments may include but are not limited to:
Any treatments needed are performed on the item. It is not usually necessary to repair all small tears. The edges of the paper is held together by static after encapsulation. Usually the less that is done to the original the better.
Item is measured and appropriate sized polyester is chosen, or cut from the roll. Thickness of the ployester is generally determined by the following criteria;
Generally the heavier sheet of polyester is on the back for support
Occasionally an original illustration, plate or photograph needs to be encapsulated and placed in the rebound or photocopied volume. The steps are as follows: