One problem remained – how best to get the hefty new air conditioning unit into the loft? The unit is 1890 mm tall, 830 mm wide and 550 mm deep, and was clearly too stocky to fit up the narrow, spiral staircase. Our only option was to investigate whether the small window, that provides access to the roof from the loft, would admit the unit.

Luckily, the unit was just smaller than the window opening. With a few millimetres to spare, a crane and small team of able bodies hoisted the unit above the roof (showing tremendous caution for the fabric of the heritage building) and slipped it into the loft space without a hitch. Here are a few photographs to illustrate the delicate operation.

Today the air conditioning unit operates within the negative cool store, providing an environment of about 18 degrees and 35 per cent relative humidity. This environment is cool enough for preservation, reducing the rate of deterioration, yet warm enough to allow us to work in the area, assessing and scanning the photographic material.

At the end of 2006 I joined the museum team and took on the mammoth task of organising, scanning, cataloguing and re-housing in conservation standard materials, this huge and largely unexplored collection. When I first climbed the narrow spiral staircase to the loft and stepped onto its coir matting I felt at once intrigued, overwhelmed and slightly intrusive. I paused, noticing the musty smell, before moving into the dimly lit space. My eyes traced the wooden shelving jutting at various heights towards the raking ceiling. The light switch flicked on to little affect. Between the tall, dark shelving I was surrounded by a towering corridor of pigeonholes. Each compartment was precariously stacked with branded boxes of varying size or grubbiness, some appeared to be failing under the weight of those above. Other boxes were damaged or without ends allowing me a glimpse at their negative content. The archive was a fascinating puzzle even before peering into silver emulsions.

The loft space that houses the collection was renovated and refurbished just over a year ago. Smooth metal shelves inside the newly constructed negative cool store now provide a home to a diverse mix of photographic media depicting many strange, provocative and mysterious subjects. My initial surreal experience of the loft is now just a distant memory. Only a few snapshots remain to remind me of the amazing changes implemented to stabilise and preserve this important resource. Over the last two years a team of staff, volunteers and interns have made a huge contribution to progressing this project. I look forward to sharing the knowledge, stories and some marvelous photographs excavated since my first encounter with the loft.