Every Wednesday and Thursday from 2007 until the end of 2009, my colleague Fred and I would work on duplicating slides as part of the archiving process of newly acquired slide-based artworks. Time-based media conservation inherited a slide duplicator, the Firenze ChromaPro 45, from Tate’s photography department where it was originally used to produce slide duplicates for the slide library to support academics and researchers with their studies. This service was no longer needed as it went out of fashion with the digital revolution.

Rod Tidnam, one of Tate’s photographers with more than 40 years’ experience has been training me to operate the ChromaPro and also on how to adjust my  eyes to the task in hand. I have learnt how to judge which colour filtration to use, how certain filter combinations would cancel each other out and what this means in relation to lens stops and exposure time.

At the start, the duplicating machine remained within the photography department, and Rod, who initially trained me how to operate it, would look over my shoulder and make sure that I had fully grasped what he had taught me by questioning my decision-making process. After a couple of months, it seemed that I was fit for purpose and it was agreed that the ChromaPro should be moved to the time-based media conservation lab.

I was a little nervous at first as these reassuring dialogues with Rod were a valuable aid for me. But it did not take long before this was overcome by working in tandem with Fred. In similar fashion, we would discuss our course of action first, then group slides according to similarities and decide which colour filtration to start with. One of us would be in charge of keeping a record of the individual settings whilst to other was in charge of operating the slide duplicator. After half a day we would swap to ease the strain on one’s eyes. We would keep a count on the total number of exposures as the hanger on which the film strip is attached during processing can only hold up to 500 exposures. This meant that we would need to notch the film and add six black exposures before and after the notch so that the lab technician would know where to cut the film in the darkroom.

The results would come back in about three hours and we would review our settings, adjust and shoot another test strip the same day. If any of our filter combinations were successful, we would process the required number of exposures immediately. As the processing bath is renewed every week there is deviation in the chemicals for which all settings had to be reviewed weekly. Rod always advised us never to process a film on a Monday as this was when the bath was most unreliable. There were instances where we tried to improve on the filtration for a certain group of slides for weeks before realising that there was no further improvement possible. It was then that we realised that we were still learning on the job.

The artworks that we started with in 2007 had already been duplicated on Edupe from the in-camera originals under the supervision of the artist and this is what Tate received as part of the acquisition. When making duplicates from slides already on the same duplicating stock, the whole process of colour matching is more straightforward than when working with master slides which are held on varying film stocks of in-camera originals.

This carried on until Kodak announced the discontinuation of its slide duplication film stock Edupe in March 2010, we were archiving David Lamelas’s Film Script (Manipulation of Meaning) 1972, which consists of a 16 mm single channel film projection and a 3-channel slide projection with a total of 69 master slides. We had been working on this since November and had four slides left to process when we had to tweak the colour filtration further. I asked Fred the other day whether he can recall if we simply stopped because we were alarmed of the preciousness of Edupe since it was no longer available, despite the fact that we had purchased a substantial stock in anticipation of this inevitable moment. We could not recall our exact conversation but I believe we were simply demoralised and uncertain how best to proceed. But in those two years Fred and I rose to the new challenge of mastering the skills needed to duplicate slides ourselves in-house.

At sone point we even discussed the option of setting up a mini E-6 lab at Tate. However we realised that despite our best efforts we were using far too much slide stock to carry out the tests before we could be certain that there was no room for improvement. We felt this was unacceptable given that Edupe slide duplicating film was now a finite resource.