Tuesday 25 June 2013

Rollei ATO 2.1

Rollei ATO 2.1 Supergraphic film
The emulsion marketed as Rollei ATO Supergraphic 2.1 used to be available as sheet film only, under the label of Maco Genius Film, but recently Maco has made it available in 35mm and 120 formats. ATO stands for Advanced Technical Orthographic, which might lead one to suppose it's an orthographic version of Rollei ATP, suggested as a replacement film for Kodak Technical Pan. However, these are both more versatile films which can be used for pictorial contrast without too much difficulty. I've had some experience with high contrast technical films, such as the Kodagraph Ortho film and Ilfodata HS23, a document film, and the general approach to using such films for continous tone or pictorial contrast is to rate the film with a low exposure index, and then either develop with a low contrast developer, or a highly dilute compensating developer such as Rodinal, which I use. I have found Rollei ATO 2.1 more difficult to control than the other films. Maco describe it as a 'true lithfilm' and to get continous tone negatives from it requires careful attention to both exposure and development. However, the film is cheap (I bought a box of ten films with an expiry date of 08/12 for €35 from macodirect.de ) and there are some advantages to being able to handle a film under a safelight.

Nominally rated 25 ISO, (although FirstCall post its speed at 32 ISO), with Rodinal, the Massive Dev Chart recommends 1 ISO and a dilution of 1:300. Maco recommend their own Rollei RLC Low Contrast film developer for pictorial contrast, or for 'normal' development (i.e. a very high contrast, lith-film look), Rollei RHC High Contrast document developer.

Rollei ATO 2.1, exposed at 25, 12, 6, 3, and 1 EI
For a first roll to test the film, I shot it with ratings down to 1 EI, and used Rodinal with a dilution of 1:200, rather than 1:300, as this would mean very low amounts of developer: with a 3-reel Paterson tank, 1:200 works out as 6ml Rodinal to 1200ml water. I kept to the Massive Dev Chart's recommended development time of 12 minutes, using 30 seconds agitation at the beginning, and a couple of inversions every minute. The results look overdeveloped, and also overexposed at 1 EI, but by 25 EI, there is no appreciable detail in the shadows (there is also, as one might expect, grain too fine to be resolved by a relatively inexpensive flatbed scanner). As the highlights still register clearly at 25 EI, it's possible to make high-contrast images with less exposure, if printed (or scanned) appropriately. However, there was a portion of this first film subject to a light leak (which may have been 'light piping' due to the particular type of extremely clear synthetic filmbase used for ATO): this suggested one way to lower the contrast of the film would be pre-exposure.

Rollei ATO 2.1 test roll, showing light leak
The principle of pre-exposure is to determine a minimum exposure where the film gains density, and use this to expose the film uniformly, then take the photograph as normal. This has the effect of raising the shadow values, while having no appreciable effect on midtones or highlights. Pre-exposure can be achieved by exposing the film in camera to a featureless, uniform surface such as a grey card which fills the entire frame before taking the shot. This is difficult to do while the film is in a 35mm camera as most do not permit double exposures, so I exposed short lengths of the film in the darkroom using an enlarger after doing a control test. This is easy to do as it's an orthochromatic film and can be handled with a red safelight. (I also spooled some lengths of the film with 127 backing paper for the upcoming 127 Day next month).

For a second test, I shot two rolls at the same time, one pre-exposed in the darkroom. Again, I used a full range of exposure indexes: 1, 2, 4, 8, 16, 32, 64 and also 25 EI. I developed these test rolls in Rodinal 1:200 again, but reduced the time to 10 minutes at 20ºC (I also used water instead of an acidic stop bath, as the emulsion on the first roll seems to have damaged easily). The results were better, and the pre-exposure did have the desired effect of raising the shadow values. In the examples below, the pre-exposed film is on the right of each pair.

Rollei ATO 2.1 exposed at 8 EI
Rollei ATO 2.1 exposed at 16 EI
Rollei ATO 2.1 exposed at 32 EI
As I did want to try the film with Rodinal diluted 1:300, I shot another roll, split in two lengths, and pre-exposed one. To develop the film I used 4ml Rodinal to 1200ml water. Compared to my previous test, the results are disappointing. I had hoped that increasing the dilution might lower ATO's innate contrast further, but instead (or perhaps as well) the negatives are extremely thin, even in the highlight areas. This may be that there was not enough Rodinal in the working solution: as mentioned in my post on stand development, Agfa recommended a minimum amount of 10ml Rodinal per film, which is conservative, as manufacturers usually are; I've found 6ml gives sufficiently consistent results. At this point I did feel frustrated at not quite getting a working combination of exposure and development.

Heygate Estate, Rollei ATO 2.1 at 25 EI
Heygate Estate, Rollei ATO 2.1 at 25 EI with pre-exposure
For a fourth roll of film, pre-exposed in the darkroom and shot at 25 EI (with some bracketing), I went back to using Rodinal with a dilution of 1:200, and ideally I would have used 10 minutes at 20ºC, but as the weather was warm and humid, the water from the darkroom tap was 22ºC, even after letting it run for some time. I reduced the development to 8 minutes accordingly, and the results below compare favourably with those using a dilution of 1:300. The high contrast of the film does make shooting any scene of normal contrast problematic if one wants to achieve detail in shadow areas without losing it in the highlights. With a minimum of pre-exposure, I've found this possible at 25 EI, although using an exposure index of 16, 12, or even 10 might provide better results. For hand-held shots using the film with available light, the slow speed of Rollei ATO means shooting at a wide aperture and relatively slow speeds (I generally used 1/50th and no smaller aperture than f4). However, I should finish by stating that this whole post is based on achieving continuous tone negatives from this film, which is not what Rollei ATO 2.1 is designed for.

Heygate Estate, Rollei ATO 2.1 at 25 EI with pre-exposure
Heygate Estate, Rollei ATO 2.1 at 25 EI with pre-exposure

3 comments:

  1. Hiya Nicholas,

    I've just bought some of this film as sheet for a 4"x 5" and found your post both interesting and useful. You talk about pre-exposing the film and your results are great. Could you tell me how long you pre-exposed the film for?

    Thanks,

    Lee

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    Replies
    1. Hi Lee,

      I can tell you exactly how I pre-exposed the film, have tested it with a range of exposures under an enlarger. I seem to remember that it was f11 for a second and a half at a height of (possibly) 40cm. However this may not be very useful without knowing exactly how bright the lamp is. It's possible to make the pre-exposure in the camera. I don't adhere to the Zone System, but essentially one would make an exposure of something blank and featureless (and not in focus) such as a white wall or large sheet of paper, and meter and place that exposure on Zone I-II and a half, and then make the shot as normal. That's a summary of the information gleaned from Ansel Adam's The Negative. I hope that helps.

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  2. It does, thanks Nicholas. I'll let you know how I get on!

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