Feeds:
Posts
Comments

Posts Tagged ‘acidity’

The Address on African Slave Trade in Houston, TX is a rare 1859 pamphlet documenting a speech given by Peter Gray, an attorney, judge, and legislator in early Texas.  The item arrived in the conservation lab whip-stitched into an aging pamphlet binder.  The pamphlet’s leaves were silked, a previous preservation treatment that has now proved problematic.  Partly as a result of the silking, many of the acidic paper leaves were torn and detached, putting them at risk for further damage and loss during use.  The acidic pamphlet binder was also causing the leaves to become more brown and brittle over time.

Before treatment: silked, acidic, broken leaves.

Before treatment: silked, acidic, broken leaves.

Critical details about the pamphlet’s structure were documented during disbinding.  The pamphlet’s leaves were folded into two sections, but typical, pamphlet-style sewing was not observed.  Instead, the item appeared to have been side-sewn several times in the past.  This restrictive sewing method is not viable for fragile, brittle paper.

During treatment: mending tears

During treatment: mending tears

Two treatment options were considered.  One approach was to re-create a modified pamphlet: rebuild broken folds, punch new sewing holes, and sew with a pamphlet stitch.  Another option was to enclose each leaf in a Mylar sleeve and bind the sleeves with stiff posts.  We chose the first, more conservative option, which preserves more of the item’s original structure.  After treatment, we judged that the paper would be sufficiently strong to tolerate gentle flexing and anticipated use.

After treatment: pamphlet is sewn into a paper case typical of its period.

After treatment: pamphlet is sewn into a paper case typical of its period.

Leaves were washed, deacidified, desilked, and resized with gelatin.  Then, the paper was mended, losses were filled, and the pamphlet was rebuilt as described above.  Replacing the whip-stitching with typical pamphlet sewing allows an unrestricted opening that will minimize future damage.  The completed pamphlet was sewn into a paper case and housed in an acid-free pamphlet binder for safe storage.

Advertisements

Read Full Post »

In preparation for our upcoming exhibit of treasured Texas icons, TSLAC Conservation completed treatment on the Travis Bible. This 1823 Bible may have been with Commander William Travis during the siege on the Alamo. At some past time, the Travis Bible sustained significant water damage, which caused its pages to swell. Major components of the outer binding had broken to accommodate the extra thickness of the paper.

One treatment goal was to stabilize the Bible’s spine and broken hinges with new leather. This process requires significant preparation, as the repair leather must first be dyed, burnished, and pared to match the binding. The leather was then shaped to the spine and adhered under the original leather on the boards, or covers. Stylistic elements of the headcaps and joints were fashioned according to typical 19th century binding aesthetics. Finally, the original spine covering was re-adhered.

Travis Bible

Dyeing repair leather

Travis Bible

Reattaching boards

A second goal was to stabilize eight silked leaves. Silking is a previous preservation strategy that reinforced fragile paper with a thin silk lining. Today, we know that silk’s acidity hastens paper’s degradation, and modern conservators instead work with pH-neutral Japanese tissue. During this treatment, the silk was removed and the leaves were mended with tissue as needed. However, three leaves of hand-written family history were especially brittle. Their ongoing use in the binding risked further chipping and loss. These leaves were removed, washed, desilked, deacidified, and housed in window mats. A custom enclosure was then created for the Bible and its removed components.

Travis Bible

Silked leaves removed from binding

630-53-Edit

De-silked leaf in window mat

The Travis Bible and other treasures will be on exhibit beginning January 27. Travis’ famous “Victory or Death” letter from the Alamo joins the exhibit February 23. A few before and after images summarize the Bible’s conservation treatment:

Travis Bible

Before

Travis Bible

After

Travis Bible

Before

Travis Bible

After

 

Read Full Post »

Since last August, I have been pursuing an informal treatment study on batches of Civil War-era documents undergoing washing and deacidification.  Today, I’d like to share some informal, preliminary results.  First, a very cursory overview of some relevant conservation chemistry.

Paper inscribed with iron gall ink, like these Civil War documents, frequently undergoes two types of degradation.  One type is caused by the presence of acid in the paper.  The second type is caused by the presence of iron ions in the ink.  Both types of degradation weaken paper, causing it to discolor, become brittle, and break.

Washing and deacidification treatments address the first problem by neutralizing pH and adding alkaline buffer.  In recent years, chelation treatments have been developed to address the second problem.  These treatments lock up iron ions and make them unable to continue damaging paper. 

I frequently pursue washing and deacidification in the TSLAC lab, and I have been considering introducing a chelation workflow, as well.  To help make that decision, I decided to evaluate the effectiveness of my current treatment by measuring acidity and iron ion presence in the Civil War documents before and after treatment.  Surface pH is measured with an Extech handheld pH meter, and iron ion presence is evaluated with iron gall test papers developed by the ICN conservation program in the Netherlands.  I classify the test paper results from 0 (no iron ions indicated) to 4 (iron ions strongly indicated.)

Given published research, I expected that washing and deacidification would affect paper pH strongly, but would have a negligible impact on iron ion levels.  My preliminary results are surprising.  Average pH increase was more modest than expected: it changed from 4.40 before treatment to 5.56 after, for an average change of 1.16.  Average reduction in iron ion presence was more pronounced than expected:  rankings changed from 1.7 before treatment to 0.4 after, for an average change of -1.3.  Not only does the after-treatment paper remain surprisingly acidic, but it also shows a surprisingly marked reduction in iron ions given that chelation was not pursued. 

These results are very informal, and testing continues monthly.  Myriad explanations can be imagined, not least including inaccuracies inherent in surface pH measurements.  (The unsuitability of destructive sampling is a frequent challenge in conservation research.)  Perhaps additional baths are needed to improve pH.  Perhaps without chelation, the iron ions become more diffuse during washing, creating risks less localized but more pervasive.  I’d be very curious to hear other conservators’ thoughts and interpretations as I consider future washing, deacidification, and chelation treatments.

Read Full Post »