The primitive emulsions used to coat dry glass plates are as we’ve already seen a little different to what we film photographers are used to these days. For a start they are a lot slower; my current J Lane plates are 2 ASA (ISO for you youngsters). As we’ve also seen already in this project, they have extremely fine grain and a beautiful tonality, a lack of an anti-halation coating and a response that dips well into the ultraviolet. This latter quality can render skies white which is something to consider when composing, it can also cause problems with metering especially later in the year here in the UK when UV levels are generally lower. Arguably, but based on my research, the optimal time for using plates here in the UK is from late March to mid-September. I shall be researching that further over the next few months.
So, on the 16th of September I headed into a patch of local woodland armed with two plates and a few loaded film holders for my fourth visit that week. The scene I chose for the dry plates was as it happened the last one of the day and I first made two exposures, one each with Fomapan 100 and 400 film, before leaving everything set up to expose my two plates. I was using the Intrepid 5×4 with an 180mm lens set at f22 and decided to leave everything as it was. I metered the scene at 12 seconds which I would need to double to 24 seconds to take account of reciprocity. From experience I knew that these plates like plenty of light so I increased that to 30 seconds and also decided to expose the second plate for 60 seconds.
I was glad that I opted for extending the exposure time as both were under exposed when I developed them a couple of days later. There was however sufficient detail in both to render them usable and I digitised them in my usual fashion before converting the negative image to a positive. I think an exposure time of 120 seconds or even 240 might have been more appropriate.
So, a very pleasing image and some more knowledge and experience gained. A very good day at the office I’d say!