Super cool! How the Digby/Woolf Lotteries project keeps negatives safe

Super cool! How the Digby/Woolf Lotteries project keeps negatives safe

Last year, Te Papa received a grant from Lotteries NZ towards the digitisation of the Spencer Digby / Ronald D Woolf Collection of around 250,000 photographic negatives shot between the 1930s and 1980s. The project is now well underway! Imaging Technician Ashleigh James-McKenna gives us an insight into how the negatives are managed.

The Spencer Digby / Ronald D Woolf collection is split across acetate and nitrate film negatives. Before any acetate film negatives can be digitised, they must be retrieved from their current storage and acclimatised to room temperature.

Where are the negatives stored?

Acetate negatives are kept in drawers in a secure vault with a controlled temperature of 2 degrees Celsius and a relative humidity of 35%. Inside each drawer, the Digby / Woolf negatives are kept in the glassine job bags they came to Te Papa in. 

A storeroom with many drawers that have boxes sitting on top of them
The coolstore at Te Papa. Photo by Ashleigh James-McKenna, Te Papa
Job bags in a drawer in the coolstore. Photo by Ashleigh James-McKenna, Te Papa

Why are they kept cold?

Acetate negatives have a tendency to degrade over time, and this process cannot be reversed once it has begun. As a form of preventative conservation acetate film negatives are kept at a chilly 2 degrees Celsius. This cold temperature slows the degradation process and prevents the image from becoming difficult to read. Degraded acetate negatives can be treated by a Photographs Conservator, but the process is time-consuming and has some risks.

This image shows the kind of damage that can occur when negatives are stored outside of optimal conditions. This is called channelling and is one of the effects that we are trying to prevent by storing negatives in a temperature and humidity-controlled environment.

Degraded negatives showing channelling. Photo by Ashleigh James-McKenna, Te Papa

How do we get them out of storage?

To complete the registration and digitisation of the negatives, they need to be moved out of the store. They must be slowly moved to room temperature and humidity, avoiding the dew point – the temperature where water droplets condense and can become dew – which can damage the negatives. The process of removing the negatives from the coolstore and to room temperature is called acclimatisation.

We gear up and head into the chilly 2-degree coolstore, armed with cold weather gear and chilly bins.

Two women in sunglasses, facemasks and cold-weather gear stand casually in an inside doorwayy
Too cool. Caitlin Watters (Left) and Ashleigh James-McKenna dressed for the coolstore. Photo by Ish Doney, Te Papa

The chilly bins help ease the negatives through the temperature changes and keep them stable, avoiding the tricky dew point. We place the negatives into the chilly bins, record the required information and move them to a slightly warmer store – a positively tropical 13 degrees Celsius – where the glass negatives are kept.

An open and empty chilly bin sits next to an open drawer of cardboard files.
A chilly bin with extra padding used to acclimatise and transport negatives to and from the coolstore. Photo by Ashleigh James-McKenna, Te Papa

The negatives stay in their chilly bins in the 13-degree store for 48 hours. Once they have acclimatised to 13 degrees, we transport them to our workspace, where they spend a further 48 hours acclimatising to room temperature, which sits around 20 degrees. After they have reached room temperature, they are ready to be registered and digitised!

What about after they are digitised?

Once digitisation has been completed, the negatives must return to the 2-degree coolstore freezer – but they can’t go straight in! They must do the acclimatisation process backwards, from room temperature to 13 degrees for 48 hours, and then down to 2 degrees for another 48 hours. Once they have fully acclimatised back to 2 degrees, they can be returned to their permanent homes.

A pair of arms in a warm neon jacket sifting through a file drawer filled with sheets of card.
Returning digitised negatives to their permanent homes. Photo by Ish Doney, Te Papa

If they are degraded, then they will be placed into a fully sealed box that will go into a dedicated film freezer that is kept at -20 degrees Celsius where they will be stored safely to ensure no further degradation happens.

Acclimatisation is just the beginning for the Digby-Woolf project, there is so much more to what we do. Keep an eye out for further blogs explaining more about what our project does and how we are going.

Explore the Spencer Digby / Ronald D Woolf Collection on Collections Online – we’re continually adding more as they are digitised.

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