https://archives.blog.parliament.uk/2017/05/24/negative-and-positive-digitising-glass-plate-negatives/

Negative and Positive – Digitising Glass Plate Negatives

The Parliamentary Archives holds a collection of glass plate negatives dating from c.1900 that were purchased from Edward Farmer, a commercial and technical photographer, in 1972. Our latest project has been to digitise this archive and make the images available on our Image Gallery. The negatives, comprising images of the Palace of Westminster, were originally created for a 1905 publication “Parliament, Past and Present – A Popular and Picturesque Account of a Thousand Years in the Palace of Westminster, the Home of the Mother of Parliaments” and were photographed by W.S.Campbell and Augustin Rischgitz.

In terms of the development of photography, glass plate negatives preceded photographic film and by the time Campbell and Rischgitz created these in the late 19th century a dry plate method, coating thin glass panes in a gelatin emulsion, had been developed. Glass plates were far superior to film in image quality and from a long term preservation point of view they are a stable format that is less likely to bend or distort. However, the organic gelatin layer can split and peel from the glass, especially if the negatives are stored in an environment where the temperature and humidity fluctuate dramatically. These fluctuations cause the gelatin layer to expand and contract, which in turn can lead to splitting and peeling. To prevent this damage occurring we store our negatives in a controlled cold storage environment that maintains a steady temperature of around 10ºC and a consistent relative humidity (RH) of around 35%.

Original packaging and rehoused glass plates

 

Any digitisation project begins with an assessment of the material by our Collection Care colleagues. Whilst the glass plates are in generally good condition, the glass side of the plates were given a light clean to remove dust and dirt. The collection was stored in its original boxes and wrappers, which were made of poor quality acidic materials and very fragile. This posed a risk to the stability of the negatives, so the entire collection was rehoused in specialist archival boxes, with plates individually wrapped in high purity pHoton™ paper and cushioned with Plastazote® foam. Some of the original boxes and wrappers were kept as interesting examples of product packaging.

Glass plate table setup

The negatives were imaged on a piece of equipment built for us by the Palace of Westminster carpenters. It’s a wooden frame supporting a glass top. We lay the negatives, glass side down, on the table, light the negatives from underneath and take a photo from our overhead camera. Using the levels graph in our camera software we can invert the negative image we capture and turn it into a positive i.e. normal image – no need for a dark room anymore!

 

Like our Stone Photographs project the Farmer glass plate negatives offer an interesting glimpse into the Edwardian Houses of Parliament and it is notable from the negatives how industrialised the area along the Thames at Westminster was. Also of interest are the people who worked in the Palace, shoeblacks, kitchen staff and policemen. We hope you enjoy these latest additions to our Image Gallery.

Early selfie, photographer's reflection in Speaker's Coach FAR_5_5
Detail from FAR_1_12 showing industrialised South Bank and Crosse and Blackwell Wharf
Detail of FAR_4_8 traffic on Bridge Street

 

Staff in the Kitchen Dept. FAR_3_22

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