interpositives from 6x6 and 35mm

Discussion in 'B&W: Film, Paper, Chemistry' started by waynecrider, Jun 1, 2005.

  1. waynecrider

    waynecrider Member

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    35mm Interpositives

    What's the largest alt print size I could expect to get off of 400 speed 35mm film when going thru a standard two step interpositive.

    What size interpositive would you choose if you had a 6x7 enlarger?
     
    Last edited by a moderator: Jun 2, 2005
  2. Ian Grant

    Ian Grant Subscriber

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  3. Deckled Edge

    Deckled Edge Member

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    Wayne,
    I have made some very satisfying 5x7 in. Pt/Pd images from 6x9 negatives. I think 5x7 may not be too large for 35mm negatives. As for the speed of the original negatives, this probably won't matter, unless you intentionally developed for grain. Since I have a 4x5 enlarger, my interpositives were 4x5. Since you have a 6x7 you have two choices: make the interpositives 35mm and enlarged negs onto 5x7 film; or enlarged interpositives onto 120 film or cut 2-1/4 x 3-1/4 sheet film, and then enlarge the negatives by projection onto 5x7. The latter would require two different sized films and two enlargment process which might degrade the image, and you would have to crop the image twice.
    On the other hand, you have a larger interpositive, which will be easier to work with and manipulate.
    I would try 5x7 first, as this is a very nice alt. image size; the format is closer to the 35mm aspect ratio, and you won't go broke (as quickly) finding out that larger formats don't work.
     
  4. Donald Miller

    Donald Miller Member

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    I concur that 5X7 would be the upper limits of what I would enlarge the 35 mm to. Perhaps even smaller since grain with 400 ISO film is going to be a definite factor.

    I would not do either a 35 mm interpositive or a enlarged interpositive on 120 mm film. The reason is that you will want to be able to determine the contrast on the interpositive. It needs to be fully exposed and developed...but it needs to be low contrast. The proper contrast is achieved when one exposes and develops the enlarged negative. The following is what I have done and it works.

    I would project my 35mm image onto the baseboard and expose 5X7 APHS film as a low contrast interpositive and then contact print this interpositive on another sheet of 5X7 APHS to arrive at the enlarged negative. The reason that I would use APHS is that it is an orthochromatic emulsion so you can work with it using a safelight. Secondly this material does not exhibit grain as conventional films do. The third reason is that it is ammedable to differing contrasts and further it is a slow speed film which makes achieving proper exposure less difficult in the darkroom. You can use dilute dektol as the developer of this material.

    The price of APHS film is also a lot less expensive then a conventional panchromatic emulsion.
     
  5. waynecrider

    waynecrider Member

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    Thanks guys... This makes more sense to me. I would also think that a 5x7 alt might be easier to sell, as that is what I intend on doing. I have Bergger's ortho, so will cut it in half. I might try APHS next time around..

    As far as low contrast is concerned, and since I haven't tried to do that before, what is the procedure? Pull from the developer; Use highly diluted developer? And would Pyrocat be ok so I can use just one developer and not have bottles all over the place? Thanks for the help...
     
  6. Donald Miller

    Donald Miller Member

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    If you want to use Pyrocat, the effects of the proportional stain will be difficult to ascertain visually. However should this be what you opt for then I would use 1-1-150 or possibly 1-1-200 dilutions and develop by inspection on the interpositive. What you want to strive for is an interpositive that appears to be flat in contrast yet containing all density information that the original negative possesses.

    Then in contact printing the interpositive on the enlarged negative I would return to Pyrocat at the recommended dilutions and times for the process that you want to do. Typically this will be 2-2-100 dilution for most of the alt process density ranges.

    This will take you a little time to sort out for yourself.
     
  7. nze

    nze Member

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    hello Wayne

    if you decide to keep print intimate, no more than 8x10, you may check this.
    http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=4204&item=3875568453
    I use this film for the enlarge negative I do which are less then 9 large. For larger print I use a direct positive method with ortho film.

    THe direct positive film is really easy to use. Kodak ask for using D19 or DK50, but I develop it in Ilford PQ at 32°C for 1 minute follow by an stop bath and fixing bath. Dektol may be use. you control the low loight by exposure and you develop to bring the highliht to the right density for the process you use. the time I note above may be use for palladium print ,Ware cyanotype, Kallitype and so on.For gum a lower temp for the develoment may be need.

    Regards

    P.S : less step, less dust.
     
  8. waynecrider

    waynecrider Member

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    NZE that is interesting, but wouldn't know how to store the stuff? Does it come in a canister. How do you use it; In pitch dark?
     
  9. nze

    nze Member

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    Wayne
    I store the stuff in my lab . It is boxed in a black plastic box , which can be keep in daylight. I open the box only under red safelight, don't use sodium. it need lon exposure under tungsten enlarger, but iit is really sensitive to coldlight enlarger. by this I mean that I need 2minute @ f8 with my dusrt laborator 1000 and a 150watt lamp ( but with this enlarger the use of the 35mm condenser lost a lot of light. But with cold light I just need 10 seconds.
    My favorite method for enlarged negative is the direct positive with ortho, as it is the morecontroable , but for most of my small enlargement this film give better result.
     
  10. roy

    roy Member

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    I take it that you then contact print this to a fresh piece of film to make a negative or do you fog it and bleach it ?
     
  11. nze

    nze Member

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    Roy
    When I use the film I linked above I do not need to fog or contact print. it give a negative from a negative

    and when I use ortho film (often bergger) I work like that:
    1. I do a test strip
    2. I select the good time and multiply by 5x (this factor depend on the film)
    3. expose again with the x5 factor and do all the dodging and burning needed, in this case more is less.
    4.develop in PQ
    5. stop
    6. wash
    7. bleached in a dichromate / sulfuric acid solution
    8. Wash
    9. expose to light( what ever the timing ) till there is no sun on the film.
    10. Clear in a sodium sulfite solution
    11.wash
    12. Develop again , I use PQ @ diferent dilution to get the Dmax I need.
    13. I don't need to fix

    SO compare to the direct positive film It is quite longer and I use much more chemicals.
    hope this help
     
  12. roy

    roy Member

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    Thanks Christian. I am with you now.