New-York Historical Society

The Preservation of 18th Century Parchment

This post was written by Janet Lee, Conservation Assistant 

Parchment is a kind of processed animal skin that has been used for centuries as a writing surface. Considered strong and stable, parchments have traditionally been used for important documents.

parchment bundles

These parchments are late 18th century colonial land grants from the Banyar manuscript collection. Like most parchments in the collection, they come to the lab folded into tight bundles, which makes storing them easy but access to them less so.

Having been folded for many years, they tend to resist being opened. They are so stiff, that even if they can be unfolded, they are creased and distorted, too unwieldy for handling.

parchment unfolded

We take advantage of parchment’s water sensitive nature to relax the fibers and flatten it through humidification. Humidification involves the controlled introduction of water as a vapor to an object. There are lots of ways to humidify parchments, and for this document, we decided to use contact humidification with Gore-tex. Gore-tex is a synthetic non-woven fabric that’s used in conservation as a barrier layer that only lets water through as a vapor.

Before humidifying the parchment, we first clean its surface of dirt. Then we introduce the vapor. This is done by lightly misting one side of the Gore-tex with water, and placing it moisture side down onto a clean surface. We place the parchment on top of the Gore-tex with a thin porous barrier between them. We then cover the entire system with a clean polyethylene sheet, which prevents moisture from escaping but also lets us observe the parchment.

parchment humidified

We use light glass weights to help ease out the creases while the parchment relaxes. We don’t humidify the document for long because too much moisture can irreversibly change it. After humidification, we let the parchment dry between layers of absorbent blotter paper and under weight.

parchment drying

This parchment unfolded to be almost 3’ x 3’. It also has a beeswax pendant seal attached with a cord, further authenticating it as an important document. Because of its size and its pendant seal, the next step will be housing this parchment in a custom-made enclosure.

parchment flat

Paper has been the more common writing surface since the late 15th century, and bundled together with this parchment is indeed a smaller document on paper. In this case, the top edge of the paper is scalloped, or cut in an undulating pattern, which reflects the traditional practice of cutting parchment for an indenture so that two or more pieces can be matched together to prove their authenticity.

paper as parchment

 

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This is a blog created by staff members in the library to draw attention to the richness and diversity of our collections.

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