Friday, 18 July 2014

127 Day - Summer 2014

Dagenham Brook, Baby Ikonta, Kodak High Resolution Aerial Duplicating Film
On last Saturday's 127 Day, I shot two rolls of Ilford Selochrome and Kodak High Resolution Aerial Duplicating Film apiece with my Baby Ikonta. The Selochrome films had a develop before date of January 1970, but I've had fairly good results with out of date Ilford 127 format films before, notably FP4 on last December's 127 Day. These Selochrome films were originally rated 160 ISO, but I shot the rolls at 40 EI to compensate for the loss of sensitivity with age. Selochrome was a brand name that Ilford used for a number of emulsions - the Selochrome roll film I used was panchromatic, whereas I have used older versions of Selochrome which were orthochromatic. To develop the Selochrome films, I extrapolated a time from the leaflet inside the box, which has data for ID-11 and Microphen. I used Ilfotec LC29; to determine a developing time, I compared the Selochrome times in ID-11 with FP3, which are the same, then used the FP4 Plus developing times with Ilfotec LC29,  but added another minute and thirty seconds as an additional margin of error.

Ilford Selochrome 127 format
I developed the first of the Selochrome films only to find that I didn't have any fixer. This oversight can be explained by the fact that I wasn't using my normal darkroom due to refurbishment, instead developing at home using a dark bag and a single reel tank. I had acquired a number of bottles of various chemicals and was under the impression one of these was fixer. Instead, I had three different types of developer, and one bottle of stop. As it was a Sunday afternoon, I wasn't able to buy some fixer there and then. Rather than leave the film in the rinse unfixed overnight, I looked online for suggestions of household chemicals that could be substituted for fixer, and came across several discussions (mainly with the same participants, such as here and here) about the use of common salt. From others' experiments, the use of a salt solution requires the film to be soaked for considerable time in a highly saturated solution. Apparently, the time can be reduced by being heated, but I didn't want to so with such an old film, fearing that the emulsion might simply separate from the base, quite apart from the chance of reticulation. Recommendations for the salt solution suggested a mix of 300g salt to 1 litre of water, which I heated to disolve the salt, cooled the solution, and then left the film soaking overnight. I also soaked an undeveloped film end to use as a control. The next morning, after around 18 hours, the film end was nearly clear, but not so transparent that I would be confident of its archival stability. I bought some Ilford Rapid Fixer to fix the Selochrome film, which was also fairly clear after being soaked overnight. Although I did take the precaution of re-fixing the film, this experiment seemed to demonstrate that it would be possible to use such a technique in an emergency, but not in a hurry.

Brick Wall & Shadows, Baby Ikonta, Ilford Selochrome
Cones, Baby Ikonta, Ilford Selochrome
127 Day, Baby Ikonta, Ilford Selochrome

The Selochrome negatives looked a little overexposed, with some fog as to be expected with films over forty years old, and there was a texture imparted on the emulsion from the backing paper, but this mainly showed up in larger areas of more even tone, such as the sky in the last photograph above.

I also shot two rolls of Kodak High Resolution Aerial Duplicating film cut to 127 size. One film I pre-exposed in the darkroom to raise shadow values, the other was shot without, although the results show no real difference. Having recently tried stand development with Ilfotec LC29, rather than Rodinal/RO9 One Shot, I also used it here. The first of these High Resolution Aerial Duplicating films was stand developed in Ilfotec LC29 at a dilution of 1:200, but, looking a little thin, I used a dilution of 1:150 for the second film. I was also using a small tank, which only held a maximum of 400ml, so the actual amounts of developer used was very small, 2ml and 3ml respectively. The best shot from the High Resolution Aerial Duplicating film is at the top of this post, all the other photographs had featureless skies, which I did expect from this high contrast blue-sensitive film, which also exaggerates the vignetting of my Ikonta's Novar lens, even stopped down.

Lea Interchange, Baby Ikonta, High Resolution Aerial Duplicating film
East Marsh, Baby Ikonta, High Resolution Aerial Duplicating film
Leyton Sign, Baby Ikonta, High Resolution Aerial Duplicating film

Friday, 11 July 2014

Kodak High Resolution Aerial Duplicating Film

Kodak High Resolution Aerial Duplicating Film SO-192
Sometimes when searching for photographic materials online, one finds quite obscure films on auction sites. This drum of Kodak High-Resolution Aerial Duplicating film was a entirely speculative bid, not really knowing exactly what it was; I calculated, that, being 5 inches wide, the 500ft of film could be cut to 1,500 sheets of 4x5. That's a lot of photographic material. It has a date of 03/2006, but given the nature of the emulsion type, unless stored in the worst conditions, this age would have little bearing on the film.

Kodak High-Resolution Duplicating Film label
Research online brought up a data sheet which provided more information about the film. The name itself is entirely descriptive, but the data sheet elaborates:
The blue-sensitive, hardened emulsions of this film is extremely fine grain and of extremely high resolving power. The film is designed for duplicating very fine grain, high-definition aerial negatives. It is intended for use as a second-generation positive and a third-generation negative.
Kodak still make a number of films for aerial imaging. This film is available to buy from selective suppliers, which may mean that Kodak are still producing it, although, like other recently discontinued films, it may be that there are sufficient stocks to meet demand for some time to come. The SO-192 code stands for 'special order': a number of Kodak films have special order numbers which denotes not only the type of emulsion, but also substrate, and other aspects such as format, perforations and so on. High Resolution Aerial Duplicating film is available on two thicknesses of film base, and each has its own SO number, SO-192 on 3.9 mils (0.10 mm), and SO-187 on 7.0 mils (0.178 mm) Estar base. As the film is blue-sensitive, it can be handled under normal darkroom safelights, Kodak recommending Safelight No.1, a red safelight, although as blue-sensitive, presumably yellow or amber would also be safe. Although not intended as a camera film, I wanted to use it as such. Information about exposure and development from Kodak is purely for its use as a duplicating film, but having used similar films before, I had some idea of the parameters of both. To make some initial tests, I cut a couple of lengths of the film (inside the large tub, the film is on a metal spool) with a rotary trimmer to the width of medium format, 62mm, and rolled these with 120 backing paper. Notably, the film itself is bright yellow. I used the first test to get a usable exposure index. I had read online that the film has a sensitivity around 2 ISO, and so shot the first tests with this in mind, bracketing exposure. The film was stand developed in RO9 One Shot at 1:150 for one hour. The contact sheet below shows the results. The frames run right to left, and are rated (first row) 1, 2, 3, 4, (second row) 8, 16, then 3, 6, (third row) 6, 12, 24, 24, (fourth row) 50, 50, with the last two frames at 6 and 3 EI.

Kodak High Resolution Aerial Duplicating Film contact sheet
I did have problems with shooting this test roll: the shots needed long exposures, some of several seconds, and as the Baldalux camera I used does not sit very securely on a tripod, there was camera shake blurring these shots, such as the image below. When developed, the film exhibited very high contrast, grain too fine to show when scanned from the negatives, very clear film base, and, as the contact sheet above demonstrates, no real latitude to the exposure. At 2 ISO, Kodak High Resolution Aerial Duplicating Film is slower than normal paper emulsions, and slower than almost all of the old glass plates I have been using recently.

Kodak High Resolution Aerial Duplicating Film (6x4.5cm), Zodel Baldalux
For a second test, I cut a couple of pieces to 4x5 inches, and shot them with the MPP Micro-Technical Mk VI camera. In this test I wanted to see if pre-exposure would reduce apparent contrast by raising the shadow values, and exposed a strip across both of the two sheets in the darkroom when loading the film holders. This is most evident in the upper of the two images below, although in the second shot this pre-exposed strip is across the top of the shot amongst the branches making it harder to judge. Both sheets were stand developed in RO9 One Shot, diluted 1+120 for one hour. The two photographs below show how important accurate exposure is with Kodak High Resolution Duplicating film as it has very little latitude: the shutter on the Xenar lens is sluggish at the slow speeds, leading to over-exposure, whereas perhaps the Tessar's shutter speeds were running a bit fast.

Kodak High Resolution Aerial Duplicating Film 5x4 inch test shot, 16.5cm Tessar, rated 5EI,
three successive exposures by progressively withdrawing the darkslide,
giving effective exposure indexes of 5, 2.5, 1.25 (left to right)
Kodak High Resolution Aerial Duplicating Film 5x4 inch test shot, 150mm Xenar, rated 6EI,
three successive exposures by progressively withdrawing the darkslide,
giving effective exposure indexes of 6, 3, 1.5 (left to right)
I shot some more of the film in large format, although in bright sunny conditions, which meant that the inherent contrast was a problem. There is very little detail in either highlight or shadow areas. The image below was scanned from a contact print, scanning from the negative may possibly provide a little more detail at either end of the contrast range.

Kodak High Resolution Aerial Duplicating Film 5x4 with 16.5cm Tessar
Under overcast conditions, I shot another roll cut to medium format. Here I exclusively used long exposures of several seconds, perhaps more accurate than slow shutter speeds such as 1/2 or 1/5th, although I did not adjust for reciprocity law failure (on the data sheet it suggests adjusting an exposure of 1 second to 2 seconds). For this film I increased developer dilution, using stand development with RO9 One Shot at 1+200 for one hour. The combination of flat lighting, accurate (but not adjusted) long exposures, and highly dilute film developer provided the best results. Although Kodak High Resolution Aerial Duplicating film has very specific applications, and is not intended as camera negative material, with the right treatment this is possible. No doubt the film would also be useful for creating negatives and positives by enlargement for alternative and contact processes.

Kodak High Resolution Aerial Duplicating Film (6x4.5cm), Wallace Heaton Zodel
Kodak High Resolution Aerial Duplicating Film (6x4.5cm), Wallace Heaton Zodel
Kodak High Resolution Aerial Duplicating Film (6x4.5cm), Wallace Heaton Zodel
Kodak High Resolution Aerial Duplicating Film (6x4.5cm), Wallace Heaton Zodel

Sources/further reading:
Kodak Aerial Films
Tom Philo's Kodak Film Number Cross Reference Table