Really old plates. It’s a rather curious experience, exposing and printing from materials that were manufactured before one’s grandfather was born. It’s a process of archaeology, really, with the same sense of opening long closed doors, wondering what lies behind. Success is variable, but results, even successful results are quite possible.
My first foray for a long time was using a pack of 5×4″ plates made by The Imperial Dry Plate Company at a date pre WW1, conceivably even before the turn of the century. Plates weren’t dated in any way at that time, one has to glean from packaging, quoted speed & other cues.
Negative (left) and positive (right) using century old Imperial Rapid plates.
A final print with some burning & dodging to level tones up. Tinted to suggest selenium toning.
If trying to use plates it’s a good idea to have a proper plate holder of the right size. In 5×4″ not too difficult. During the transition from plate to sheet film, which took decades, a lot of double dark slide holders were made with metal sheath inserts, and if these are removed you’re straight back to a plate holder. There should be enough showing up on Ebay anyway. Maybe try Mr CAD as well.
Speed (see below as well) – using a conversion from H&D speed to ISO gave a speed of 6 ISO, so that was doubled for good measure, rating at 3 ISO. 2 plates were made, & developed differently, one in the sharp-working Rodinal, and one in a fine grain formulation, Ilford LC29 1+29. Development was by inspection using infrared goggles, which is a luxury not available to most darkroom workers, but it certainly simplifies timing.
It worked! Results – both plates produced pretty much the same density range. Both had a light veil of fog, but not sufficiently dense to affect the printing quality. The one shown here was the plate developed in LC29 fine grain developer.
So why do they work at all? It seems to fly in the face of all reason, with a more than 100 years age since manufacture. Most modern films a fraction of that lifespan will show high fog with normal processing. The answer has to be the evolutionary niche they fall into. The first dry plates arrived in the 1870’s, but even by the Edwardian era there had been relatively slow progress, emulsions were not only slow, but were mainly still blue sensitive, as was Imperial Special Rapid. Once sophisticated dye sensitisation came on the scene materials became increasingly faster, but the boat was being pushed further out, emulsions were a finely tuned cocktail using many trace ingredients & sophisticated mixing to push the speed higher & control the subsequent tendency to fog rapidly. Consequently with modern materials one cannot expect good performance for too many years after manufacture, but with an old blue sensitive plate you may get lucky. Another factor working in the old plates favour is that they are factory packed in pairs, emulsion to emulsion. This effectively almost vacuum packs them in an inert environment, as air is virtually excluded & the glass base itself is an inert barrier to air. There is fog creeping in from the edges, as you can see above, but it hasn’t got very far.
Dating Imperial plates
The tests were made on one of 2 packs of Imperial Special Rapid plates. The 5×4″ plates in the images above exposed above are marked as H&D 250, with a batch number 6492F. The other pack of quarter plate Special Rapid are labelled as H&D 200, with a batch no. 8605B.
By the end of the 19th century emulsion speed science was still in it’s infancy, but the leading authority was the work of Hurter & Driffield, and Imperial had adopted this & marked their plates with an ‘H&D’ number. This was being gradually increased as emulsion research pushed forward. In 1911 Imperial Special Rapid plates were advertised as H&D 200-225.
So although it’s difficult to be certain of this, because the batch number on the 5×4″ plates is lower, I’m assuming they pre-date the 1/4 plates – it’s almost unknown for a backwards counting batch system to be in operation. This is despite the 5×4″ pack showing a higher speed, it may have been a lucky batch that came out on the high side, as it was a very inexact science then. The dates of manufacture of both, then, are the sunny Edwardian days prior to WW1, when a large part of Cricklewood was leafy & unspoiled. The developers had barely started, and the Imperial Cricklewood factory, like the Ilford one, was established on a virtually green-field site.
The Imperial Company
The Imperial Company was founded on the expertise of an emulsion chemist, Joseph J Acworth. Apparently with a private income, which must given him much professional latitude, he became a Fellow of the Chemical Society in 1875, and a Fellow of the Institute of Chemistry in 1878. He was associated with Alfred Harman, the founder of the company that became Ilford, but this lasted only a couple of years before he left to work on dye sensitisation of emulsions at Erlangen University, where he obtained a doctorate. Back in England by 1892, Acworth built a private laboratory at Cricklewood for experimental emulsion research, which became the Imperial Dry Plate Company.
At a time when a lot of manufacturers were using some sort of Arthur Rackham influenced fantasy advertising, Imperial’s was… well, rather strange.
The quality of the products Imperial produced seem to have been exceptionally high, and they were obviously significant competition to Ilford. Eastman Kodak in the US had on several occasions made predatory moves towards the British photographic film & paper manufacturers, and the path ahead seemed to be amalgamation in the UK to strengthen the UK industry. At the end of WW1 Ilford worked towards uniting the significant number of British photographic manufacturers by acquisition, and Imperial must have been top of the list. Acworth had retired in 1912, and it must have been felt this was the right time to make a move. The Imperial company, along with Ilford’s other acquisitions were run quite autonomously, but emulsion knowledge was shared, and many business functions such as central purchasing made them jointly more effective. The Imperial Company was later fully absorbed into Ilford Ltd, but the works were only finally vacated as late as 1967.
The Imperial Factory
Built in 1892 by George Furness, who built most of the housing in Cricklewood at that time. The Imperial factory is now long gone, but the location of it is easy to find, where a large mansion flat development, Ashford Court sits firmly across the site.
(left) 1894 OS Map, (right) the location transferred to a 2016 Google Earth image
A full account of the lives of Joseph J Acworth & his wife is here;
… and thanks to Dick Weindling and Marianne Colloms for the use of the map & other information.