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Though our conservation lab at TSLAC focuses primarily on books and paper, we also care for the non-paper-based archival items found in our collections.  This month, we created a housing for an undated photographic glass plate negative from the Sam Houston Regional Library and Research Center in Liberty, TX.

A glass plate negative consists of photographic emulsion cast on a glass plate.  The negative image on the plate is later developed into a photographic print.  Glass makes these negatives very fragile.  When they break, their fractured edges begin to abrade one other, causing more damage to the glass and the media.

Broken glass plate negative in modified sink mat.

Broken glass plate negative in modified sink mat.

Our housing is based on a design from the National Archives.  The broken negative is stored in a covered sink mat for protection.  Small spacers separate the broken pieces to minimize abrasion.  The mat is stored flat in a box with a warning label regarding careful handling.

Detail of spacers separating broken fragments.

Detail of spacers separating broken fragments.

The outer mat edges are hinged, allowing the item to be removed from its housing as needed.  However, future removal should be rare, since the image was scanned before treatment.

Scanned image from glass plate negative.

Scanned image from glass plate negative.

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TSLAC Conservation has recently worked on several panoramic photographs. Popular for documenting sweeping landscapes or large groups of people, panoramic photos are created with specialty equipment and large-format developing processes. Many images date to the early part of the 20th century and measure 10 – 12” tall by four, five, or even six feet long.

Panoramic photos are commonly found rolled, as seen in this item awaiting treatment:

Tightly-rolled panoramic photograph.

Tightly-rolled panoramic photograph.

Rolling is a common non-archival storage method due to the typical size of these items. Rolling can also happen naturally, due to the differing ways humidity impacts the photograph’s paper backing and image layer. Once rolled, these photos strongly resist being forced flat. Doing so often results in disfiguring cracks, as seen in this recent donation:

This sharp crack is typical of those caused by forcing a rolled panoramic photo flat.

This sharp crack is typical of forcing a rolled panoramic photo flat.

To avoid this damage, conservators humidify panoramic photos, open them very slowly, and then allow them to dry under weight. Once flattened, these items are at new risk for rough handling due to their unusual size. Proper housing can minimize handling damage and curling.

There is no single, standard housing for panoramic photos. Our design features a support of 40-pt box board with a cover sheet of archival plastic. The plastic sheet folds over the support board at top and bottom. The bottom fold is secured to the back of the board, while the top fold remains unsecured.

Housed panoramic photo depicts a group of people at the Texas State Capitol, possibly WWI-era.  Archivists can work to identify this image now that access is improved.

Housed panoramic photo depicts a group of people at the Texas State Capitol, possibly WWI-era. Archivists can work to identify this image now that access is improved.

The housing keeps the item flat, supported, and easily viewable. If needed, the photo can be removed from the housing without scratching by lifting the cover sheet. Future housings may use a micro-corrugated support board for improved rigidity and reduced weight.

To learn more about TSLAC’s photography collection, stay tuned for our exhibit of 19th century photography opening in late September 2014.

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