Wednesday, 30 October 2013

Air Ministry Plates

Box of Panchromatic Photographic Plates produced for the Air Ministry
In my post Recent Glass Plate Work-part two I mentioned that 5x4 plates don't appear in auctions very often in comparison to other sizes. Since then I've only found one box of 5x4 inch glass plates, but one that's an interesting curiousity. The plates in the sealed box are described simply as 'Plates, Photographic Panchromatic'. The label is printed with the initials 'A. M.' which, with the crown symbol, stands for the Air Ministry; the Air Ministry existed from 1918-1964 before being subsumed into the UK's Ministry of Defence. The box has a maker's identification number ('TE12') which could be used to discover which company made the plates, but this isn't the sort of information that can be readily found on the internet. The date of coating appears to be '12/5/34' (it's just possible that the partially stamped digit is a '5' for '54' but comparing it to the '5' present, it does look like a '3'). These are the oldest securely dated glass plates I have used (the box of Mimosa Porträtyp-Antihalo plates might be older, but are not dated like this box).

As I wasn't expecting much from the plates at this age, I didn't do a test before shooting a couple of plates, on the same night as I shot some more Ilford G.30 Chromatic plates. I stand developed all the plates in Rodinal 1:150 for 1 hour 20 minutes (using the dilution of 1:150 rather than 1:100 in an attempt to keep the contrast of the night scenes down). Having low expectations, I was surprised by the results, which were a little thin, but printable. What was also notable was the backing: on most other plates I've used this washes off during the developing process. I also usually soak the plates in water before stand development for 2-5 minutes, but with the Air Ministry plates, the backing is thick and gelatinous, and during the final wash stage I had to take each plate out of the wash individually and use my fingers to rub away the backing.

Air Ministry plate, MPP Micro Technical Mk VI with Schneider Kreuznach Xenar 150mm f4.5 lens.
Scan from contact print.
Air Ministry plate, MPP Micro Technical Mk VI with Schneider Kreuznach Xenar 150mm f4.5 lens.
Scan from contact print.
After the initial results, I decided to use one plate to make test exposures in order to determine a working exposure index. The box gives no indication of the original speed of the plates, but comparing the exposures of the first two plates against the results of Ilford G.30 Chromatic plates previously shot, I reckoned the Air Ministry plates to be around half as sensitive.  For the test, I metered the scene at 6 EI, and made three successive exposures on the plate to give 6, 3 and 1.5 exposure indexes. It is a little hard to judge the results, partly as the background fog pulls up the shadow values, at 6 EI there is a lack of shadow detail, but the middle exposure at 3 EI looks to be printable (the image from the plate below is a scan from the negative).

Air Ministry plate test. Three successive exposures at 6 EI.
I subsequently shot another couple of the Air Ministry plates at night, choosing for the first plate a difficult subject with the brightly lit building against a foreground which is almost featureless; the second plate, a longer exposure to use a smaller aperture for greater depth of field (18 minutes at f8) shows more effects of age on the plate. Apart from a few spots, all the plates show marks from the cardboard runners holding the edges of the plates in pairs in the wrapping, but generally, for glass plates which might be 79 years old, the results are impressive.

Air Ministry plate, MPP Micro Technical Mk VI with Carl Zeiss Jena Tessar 16.5cm f5.3 lens.
Air Ministry plate, MPP Micro Technical Mk VI with Carl Zeiss Jena Tessar 16.5cm f5.3 lens.

Thursday, 17 October 2013

Ilford FP4 Plus

Ilford FP4 Plus in medium format rollfilm, 35mm and large format sheet film
FP4 Plus is Ilford's fine-grained medium speed complementary to HP5 Plus. Ilford introduced emulsions at different times in different formats, and according to the product index in Silver By The Ton, the earliest emulsion given the name Fine Grain Panchromatic appeared as sheet film in 1930, rated 30 ISO, with rollfilm formats following in 1935, and glass plates in 1937. The name FP4 was first used for glass plates in 1955, with the full name Fine Grain High Speed Panchromatic and a speed rating of 160 ASA (post 1960 revision in film speeds), although according to Photomemorablia this was not the same emulsion as the film version, available from 1968. The rollfilm FP4 emulsion was rated 125 ISO, which it remains to this day in its current 'Plus' iteration, introduced in 1990. (There was also an FP Special glass plate introduced in 1949, with a speed of 80 ASA). FP4 Plus is currently available in 35mm, 120, and numerous sheet film sizes.

In my post on HP5 Plus I wrote that it had been the default black and white film for me at one point, and, partly due to the kind of photographs I used to take, I tended not to use films slower than 400 ISO. This was the case for many years (when I didn't have access to a darkroom I mainly used Ilford XP2), until I returned to developing films myself. Subsequently, using Rodinal as a film developer has led me to be a little more discerning over my choice of the films due to its effects on grain, and, although I still use HP5 often, I started using FP4 around the same time.

FP4 Plus has many characteristics similar to HP5 Plus: although it is slower and finer grained, the film still possesses good latitude, and, as a traditional cubic-type emulsion, it has a similar look. The Ilford FP4 Plus technical information sheet gives a recommended range of meter settings from 50-200; it also gives development times for 'accidental exposure' at 25 and 400 EI with a couple of specific developers (on the Massive Dev Chart, there are ratings from 25-1000 EI, depending on the developer used). I've only developed FP4 Plus with Rodinal, and usually at box speed (although with my Olympus Pen EE3 half frame camera, I like the look of the film with a slight push to 200 EI). Using Rodinal, particularly in 35mm, the results I've usually liked best are those at higher dilutions, mostly at 1:50, but also I particularly like FP4 when stand developed in Rodinal diluted at 1:100. Additionally, I usually develop at sightly lower temperatures than the standard of 20ºC as this also has a bearing on the appearance of grain. With the exception of the first example below (a demonstration print made for a black & white film photography introduction), the rest of the images are scanned from the negatives.

Ilford FP4 Plus (35mm half-frame), rated 200 EI, developed in Rodinal 1:50, 25 minutes at 18ºC.
Scan from print on Ilford MGIV RC.

FP4 Plus (35mm), developed in Rodinal 1:50, 18m30s at 18ºC.
FP4 Plus (35mm), developed in Rodinal 1:25, 10 minutes at 19ºC.
FP4 Plus (6x9 medium format), shot at box speed, developed in Rodinal 1:50, 18m30s at 18ºC.
FP4 Plus (35mm half-frame), shot at 200 EI, developed in Rodinal, 1:50
Grand Palais, Paris; FP4 Plus (6x4.5cm medium format), rated 125 ISO, developed as 200 EI in Rodinal, 1:50, 24m45s at 18ºC


Silver by the Ton - A History of Ilford Limited 1879-1979, RJ Hercock and GA Jones