Sunday, 22 April 2012

More Glass Plates

Kodak O.250 Rapid Ortho Metallographic Glass Plates
Following the successful results exposing and developing old Ilford R.10 glass plates, I wanted to test another box, again previously opened. These are Kodak O.250 Rapid Ortho Metallographic Glass Plates and, according to the Early Photography website, Kodak's Rapid Ortho emulsion was only available in plates. These are 6.5x9cm plates, slightly larger than the imperial size of the Ilford plates (the small handwritten label on the box states: "Do not fit 3 1/2x2 1/2 single slides"). The box is also inscribed with a marker pen '28/6/62'. The plates in this box, unlike the Ilford plates, are wrapped in fours, with the central pair held together by paper runners. It wasn't clear which way around the plates were facing: whether the central pair were facing, and the other two facing outwards, which was the choice I made when loading the plate holders. This turned out to be the wrong decision, as the emulsion on the central pair faces outwards, the outer plates facing inwards. As a result, in the plate holders, the anti-halation backing faced the lens. I shot these plates at the same rating as the Ilford plates, roughly 12 ISO. The plates do not have a speed rating other than the name O.250, but looking at the information on Early Photography, it looks as though these plates may have been as slow as 16 ISO originally.

Kodak O.250 Rapid Ortho Plate, loaded back to front, shot in Icarette L
When I took the plates out of the holders in the darkroom under the safelights (these plates being orthographic) I realised my mistake. However, I went on to develop the plates, using the same method as the Ilford R.10 plates, using Rodinal diluted 1:100, stand developing for an hour. The results show that the anti-halation backing transmits enough light to give a fairly good image on the emulsion, but the backing wasn't a smooth, even layer (which I could see before developing), with the effect of creating mottled patches which also diffuse the focus in these areas. The negatives are quite thin but the plates are clearly usable, and perhaps shot the right way around the negatives would be sufficiently dense to use at 12 ISO.

Kodak O.250 Rapid Ortho Plate, loaded back to front, shot in Icarette L
Edit: 28/04/13

I recently bought another box of Kodak O.250 plates, and this had an information leaflet inside. It gives the speed of the plates as 8 ASA for daylight, and just 3 for tungsten, but it isn't clear whether the plates are from before or after the black & white speed rating change of 1960: if from before, then the original rating of the plates would have been 16 ISO. Either way, the plates have lost very little sensitivity despite being fifty years old. It provides filter factors and developing times for D61a and D76 (Ilford's ID11). The leaflet describes O.250 plates as being:
recommended for photographing biological sections, metallurgical and mineralogical work, spectography and macrography and clinical photography where neither red sensitivity nor high speed is necessary. It is also suitable for commercial, landscape and architectural photography and for studio portraiture by daylight.
Kodak O.250 Plate leaflet (front)
Kodak O.250 Plate leaflet (back)

Saturday, 21 April 2012

Kodagraph Ortho Negative Film

Most photographic films still in use today are panchromatic, that is, sensitive to the spectrum of all visible light. However, the earliest photographic emulsions were only sensitive to blue light; the sensitivity of emulsions was first extended to be orthochromatic (sensitive to all but red light), before becoming panchromatic. Some manufacturers still produce orthochromatic films (such as Adox Ortho, the film I first used with my large format camera) but for many years the primary use of orthochromatic film was for graphic arts applications as a result of being high contrast and fine grained, applications such as preparing black and white artwork for printing: these processes have been entirely superseded by digitisation.

Kodagraph Ortho Negative ON4 Reproduction Film
I bought this box of Kodagraph Ortho Negative Film ON4 in a batch of orthochromatic films and plates (which also included boxes of Kodalith Ortho Film Type 3 and Kodak Orthochromatic plates). The ON4 box was already opened and the only one of the three that was in a size that would fit any of my cameras without modification. Searching on the internet for information about the Kodagraph ON4 film, I found a Kodak data sheet for the Type 3 film, and plenty of references to Type 3 on forum posts and so forth, but there seemed to be nothing about ON4. The label on the box calls it 'Reproduction Film'; it has a catalogue number 326 2680 and a 'develop before' date of 9/1982, as well as instructions to open under Kodak Safelight No.1/No.1A, i.e. a red or light red safelight.

Opening the box under a red safelight, two things were immediately apparent. The film does not have notches to identify which is the emulsion side, like most sheet film; examining it under the safelights, one side looked a lighter grey which I thought could be the emulsion side. There is also the possibility that the film doesn't have an anti-halation layer (no colour came out during pre-soaking) meaning that it wouldn't matter which side is used. Loading it into the film holders, the film base is much thinner than other sheet films I've used, and I initially picked up two sheets together before I realised that how much thinner it is.

London 2012 Olympic Site, shot on Kodagraph ON4 rated at 6 ISO, developed in Rodinal 1:120
I shot the film using my MPP Micro Technical camera. I rated some sheets at 12 ISO and some at 6 (the box does not list a speed rating, the data sheet for the Kodalith Type 3 film gave 12 ISO with 'pulsed xenon' and 8 ISO for tungsten; I assumed that the ON4 film would be similar, given it was designed for similar applications). Those shot at 6 ISO were better but perhaps a little underexposed. I tray developed the film by inspection under safelights in the darkroom, using Rodinal, diluted to 1:120 with the intention of controlling the contrast. Once developed, the clear areas of the negative are remarkably transparent, with almost no discernible base fog, perhaps surprising for film 30 years out of date, but slower film tends to take longer to lose sensitivity.

For a second test shoot, I pre-exposed some of the film in the darkroom using an enlarger. Ansel Adams in The Negative describes using pre-exposure to improve shadow detail in high contrast scenes; I wondered if this would work for high contrast films. This can be done either in camera, or in the darkroom when loading the film. I exposed a sheet of film under an enlarger as a test, to find the shortest exposure which gave a discernible density on the film. I shot a number of sheets of the same subject, both with and without pre-exposure. However, the negatives from this second shoot I took out of the developer far too soon, with the result that they were all extremely thin, and as a result I haven't attempted to scan any of these. Part of the difficulty of tray developing film under a safelight is the fact that despite being able to see the image appear on the film as it develops, the film is still opaque until it is fixed, by which time it's too late to decide it needs longer in the developer, and this opacity can make the image appear denser than it is.

London 2012 Olympic Site, shot on Kodagraph ON4 rated at 5 ISO, developed in Rodinal 1:100
For the third test shoot I rated the film at 5 ISO, and again I pre-exposed some sheets. I also shot some Fomapan 400 at the same time, for a meaningful comparison of the Kodagraph ON4 with a panchromatic film. When these were developed I couldn't discern a difference between those with and those without pre-exposure, but having tray developed the film, I hadn't used consistent times so the testing regime wasn't really rigorous enough to tell. I diluted the Rodinal to 1:100 this time, which may have made the results a little higher in contrast than my first tests, but the lighting conditions were different too. The negatives are noticeably a little uneven, which can been seen in the sky, an issue due to not agitating the film sufficiently while developing.

London 2012 Olympic Site, shot on Fomapan 400, developed in Rodinal 1:50
The two films have very different looks, although the lighting conditions changed as I shot the Fomapan (which was shot with a yellow filter with to add some contrast in the sky, as well as pulling up tones in the foliage; I haven't tried ON4 with a yellow filter). The ON4 has a colder, harder look, which might suit architectural subjects for example. It also has extremely fine grain, and the slow speed is not necessarily an issue with large format film, large format cameras usually being used with a tripod.

Kodagraph ON4 rated 5 ISO, developed in Ilford Multigrade 1:30
I also developed some sheets in Ilford Multigrade paper developer, which I had used for developing the test to establish a minimum density for the pre-exposure. I diluted the Multigrade initially at 1:14, but, seeing the first sheet develop very quickly, I diluted the developer further, to roughly 1:30. The resulting negatives are very high contrast, losing detail in both highlights and shadows. This was to be expected, and, I imagine, closer to the results the film was designed to achieve.

Ansel Adams, The Negative, 1981 ISBN 0-8212-1131-5

Thursday, 5 April 2012

Ilford R.10 Glass Plates - First Test

Ilford R.10 Soft Gradation Panchromatic Glass Plates
The first old films I had developed, or used and developed, I'd come across by accident, usually finding them in or with cameras I'd bought, found or been given. Having achieved results of varying success, I began to seek out expired films on occasion, when able to find them cheaply, and this then extended to glass plates. I have a few cameras which take plate holders, which I had previously used with film or paper.
Having accumulated a few boxes of glass plates, recent sunny weather provided me with the excuse to try some. A couple of the boxes had already been opened, and it made sense to use plates from one of these first. I chose Ilford R.10 Soft Gradation Panchromatic plates, which I'd bought in a lot with a box of unopened FP4 plates, not knowing whether the plates in the open box had been exposed to light or not. Both boxes have writing in pencil with the date 2/9/65 and 'Photo Centre'; the box of R.10 has "6 8 [crossed out] left". According to the Ilford chronology on the Photomemorabilia website, glass plate production by Ilford finished in 1975 (Ilford do still make photographic glass plates for specialised applications in the nuclear and particle physics industry; some other manufacturers still make plates for general photography, but these are very expensive and a number of photographers coat their own glass plates).

The box originally held 12 plates, 2 1/2x3 1/2 inch size. There are a number of standard plate sizes, both metric and imperial, and a confusion sometimes arises between the closeness of the different sizes: metric and imperial standards are sometimes treated as being interchangeable. There is a metric 6.5x9cm plate size, which is very close to the 2 1/2x3 1/2 imperial size (being 6.4x8.9cm; I have a box of 6.5x9cm plates which has a handwritten label "Do not fit 3 1/2x2 1/2 single slides"). I used 6.5x9cm plate holders, which the imperial size plates will fit, while metric plates of that size wouldn't fit into similarly sized imperial holders.

The camera I shot the plates in is an Ica Icarette L, a dual format camera from the 1920s that takes either 120 film, or 6.5x9cm plates. When I bought this, it came with a plate holder wallet containing four single plate holders, and the following leaflet:-

Ilford Plates leaflet - outside
Ilford Plates leaflet - inside
There's a code on the back of the leaflet, 'G57/D' - possibly referring to its date i.e. 1957. Under 'Packing' it explicitly states that "plates are packed in pairs with the emulsion sides face to face," something I had previously read on a forum, which was good to have confirmed. The pairs of plates are wrapped in black paper, with a thin paper 'runner' holding these together along the short edges. The glass is very thin, less than 2mm and the cut edges of the glass are still sharp.

The R.10 plates were originally rated 100 ISO (the label around the box gives 'Meter settings for minimum exposure ASA 100 DIN 21'). With my previous experience of using out of date film (see the posts about Verichrome and 127 Day), and knowing that the sensitivity would have decreased with time, I shot two plates, the first at 25 ISO, and a second at 12. Exposure was 1/50th at f5.6 and f4.5 respectively. I stand developed the plates in a Combi Plan tank using Rodinal diluted 1:100 for one hour, with 2 minutes pre-soak, and 3 inversions at the half hour mark. The first plate came out black - this one would have been at the top of the box, possibly this had been exposed to light with the box opened at some point, although I'm not ruling out making an error myself. The second plate has a small amount fogging at the left and bottom sides. Once fixed and washed I did not squeegee the plates, but even so the plates took a long time to dry. (Incidentally, I've been reading Ansel Adams' The Negative recently, and in a section on water bath development, Adams compares older thick emulsions favourably to modern thin ones, perhaps the emulsion on the R.10 plates is thicker, and so absorbs more water). The second plate came out well:-

Ilford R.10 glass plate, shot with Ica Icarette L
Aspects of framing and focus of the plate not withstanding, there is something precious and unique about holding a glass negative in one's hand: there's probably a longer essay to be written about how the ease of taking thousands of digital images, compared to dozens on a roll of film, or single sheets, plates and Polaroids, has devalued the photographic image; it may be something to do with the physicality of the image and its physical link (perhaps misconstrued) to authenticity.

Edit: 29/04/13

As a result of my research into Ilford, I discovered the Ilford Technical Information Book, which contains a sheet on the R.10 Soft Gradation Panchromatic plates, dated to 1967. This provides additional information for the plates from the leaflet shown above. It gives the ASA setting for tungsten lighting as 64, against the daylight setting of 100. The table of development times gives further dilutions and times for both continuous and intermittent agitation.

Ilford R.10 development times
Ilford R.10 Curves