The National Coal Board collection at Glamorgan Archives includes a large amount of photographic negatives on both plastic and glass supports.
The glass plate negatives, approximately 5440 in number, feature a range of subjects, including images of tunnels, miners in action, equipment, pit ponies, medical centres, social events and other varied content.
As part of the Glamorgan’s Blood project, this photographic material will be catalogued, cleaned, digitised, conserved and re-housed, allowing public access to these images.
While the majority of the glass plate negatives simply need cleaning prior to digitisation, some display more extensive conservation issues. A number of the plates are broken or have lifting or highly damaged emulsion (fig.5). These issues will require more supportive housing solutions or more intensive conservation treatment.
Undamaged but dirty glass plate negatives require cleaning prior to digitisation and re-housing. Surface dirt on these items can contribute to long term deterioration and be visible on the digitised image. It is important that the plates be properly cleaned before any further steps in the preservation process can be taken.
To clean the plates, first an air-puffer is used to remove loose dust and dirt on both the emulsion side and the glass side. By using this tool, the emulsion side of the plate can be cleaned without risk of abrasion. Next, cotton wool buds wrapped in fine tissue and dipped in a solution of water and ethanol (50:50) are used to remove dirt and grease from the glass side of the plates. A final wipe, using a dry cotton wool bud, removes any streaks.
The cleaned plates are then re-housed in folders made from material up to PAT (Photographic Activity Test) standards. We use different sized folders for the varying plate formats to ensure a good fit (fig.6). The original packaging for these items was glassine envelopes, which is a type of highly calendared paper often found used for the storage of photographic negatives. Glassine is an inappropriate storage material as it yellows over time and can damage the photographic emulsion (fig.7).
Once cleaned, the plates are scanned and a positive image is created. This will then be added to the Archive’s catalogue.
Broken glass plate negatives require housing which both supports the fragments but also keeps them separate to ensure the delicate emulsion is not damaged through abrasion between the glass shards. The new housing incorporates cushioning plasterzote foam within an un-buffered card enclosure. This new enclosure allows the negative to be safely stored and, if necessary, viewed without removing the individual shards (fig.8 & 9). This simple housing solution can provide either temporary or long term storage, allowing for further repair treatment to be carried out in the future.
The broken negatives will also be scanned and digitised, reducing the need for handling while at the same time ensuring public access to these wonderful images.
Stephanie Jamieson, Glamorgan’s Blood Project Conservator