From the Lab: Conservation of a Pre-Revolutionary War Broadside

This post was written by Catherine Stephens, Enhanced Conservation Work Experience Assistant, Summer 2016.

In Colonial America, broadsides were one of the fastest ways to spread news, rally support for a political cause, or to advertise for popular products and entertainments. These unassuming paper notices were printed in large quantities and were displayed publicly or distributed by hand in town squares and other public meeting places. The broadside pictured above was printed in New York on April 21st, 1774, only five months after the Boston Tea Party took place. This particular notice seems to be calling on the people of New York to gather in a similar act of protest against the despised taxation measures pursued by British Parliament against its American Colonies.

For the New-York Historical Society’s upcoming exhibit, The Battle of Brooklyn and the Fall of New York (opening September 2016), the Conservation Lab is currently preparing some of these historic broadsides for display. As is often the case in the conservation of library materials, it was necessary to undo a previous treatment which had been performed on this item some decades ago. The broadside had previously been adhered to a piece of linen cloth, which extended beyond the edge of the printed paper.

While this cloth lining may have extended the broadside’s life in the short run, Exhibitions Conservator Heidi Nakashima determined that the cloth ought to be removed and replaced with a more archival and display-appropriate alternative.

The first step in the treatment process was to surface clean the front and back of the broadside with white vinyl eraser crumbs, from a Staedtler Mars Plastic eraser. The eraser crumbs gently remove any dust or surface dirt on the paper, and this prevents the creation of new stains when water is introduced. Next, because the backing cloth was to be removed in a bath of water, the printing ink was tested to see if it might be water-soluble.

This test was done by placing a small drop of de-ionized (highly filtered) water directly onto the ink in an inconspicuous area, and allowing the drop to sit for about thirty seconds. This test was repeated twice, and fortunately the ink showed no signs of dissolving or changing color.

Before placing the broadside in a bath, water was introduced slowly by misting the paper with a fine spray. The item was then placed in a tray of de-ionized water and allowed to sit for about 10-15 minutes, allowing the paper’s impurities and built-up acids to dissolve. Sometimes paper is so acidic that the bath turns yellow or even brown, but in this case the water stayed clear.

Sometimes, if the glue is weak enough, the backing material will loosen and float away during washing, but in this case the glue was stubborn and needed a bit more persuasion to release the cloth from the paper. Once the glue had softened in the water, the linen backing was slowly teased away from the paper with a teflon tool, and the freed broadside was given a bath of fresh water to dissolve any left-over adhesive.

In a third and final bath, the paper was soaked for 15 minutes in a dilute calcium hydroxide solution, with a pH of approximately 8. This last bath will hopefully slow down the broadside’s natural aging process by neutralizing some of the acids present in the paper fibers.

After the last bath, a sheet of thin Japanese mulberry paper was cut slightly larger than the broadside. This Japanese tissue might seem light or flimsy, but it has very long paper fibers which make it a very strong and durable lining material.

The tissue was adhered to the broadside with a watery solution of wheat starch paste, a “reversible” adhesive, so that the new lining can be easily removed in the future, if necessary. Once the two sheets were adhered, they were tamped down with a stiff brush, to avoid bubbles between the layers of paper.

At last, the newly-backed broadside was allowed to dry slowly between thick wool felts and plywood boards, ensuring that the paper would not curl during the drying process.

Once the broadside had dried completely, the benefits of this treatment could be clearly seen and felt. Throughout nearly 250 years the broadside had sustained many small tears along its edges, but now the adhered layer of Japanese tissue will prevent these tears from becoming any worse. Similarly, introducing water into the paper fibers has made the broadside feel “younger” and more supple, and the new backing material is thin yet strong enough to support the fragile paper when it is handled in the future.

I’ve learned so much from the Conservation team at N-YHS in this short space of time.  I will be sorry to leave in July! I’d like to thank Heidi Nakashima (Conservator for Loans and Exhibitions) for all of her guidance during this treatment, and my thanks to Alan Balicki (Senior Conservator) and Janet Lee (Conservation Assistant) for their help and advice during my four months employ in the Conservation Lab. I would also like to extend my gratitude to those who support the Enhanced Conservation Work Experience program.  They make it possible for anyone with varying degrees of experience to gain and improve their conservation skills in the N-YHS Conservation Lab.

We hope that you enjoyed reading about this treatment, and that you can visit the New-York Historical Society in September to see the completed Battle of Brooklyn and the Fall of New York exhibition!