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  1. #1

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    Enlarged B&W neg from Colour negs

    I have a series of shots that I took on 35mm colour neg film which I want to enlarge onto B&W 5x4 neg film (or larger where necassary) for contact prints. I beleive I will need an inter-positive in the process but would love some advice.
    I have a 5x4 enlarger (inc 35mm inserts) and 5x4 film holders at my disposal.
    Any advice on what process, materials to use and what the pitfalls maybe would be gratefully accepted

    Phill
    It is not tradition that secures the survival of our craft, its the craft that secures the survival of our traditions.

  2. #2

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    Quote Originally Posted by philldresser
    I have a series of shots that I took on 35mm colour neg film which I want to enlarge onto B&W 5x4 neg film (or larger where necassary) for contact prints. I beleive I will need an inter-positive in the process but would love some advice.
    I have a 5x4 enlarger (inc 35mm inserts) and 5x4 film holders at my disposal.
    Any advice on what process, materials to use and what the pitfalls maybe would be gratefully accepted

    Phill
    Phill,

    If you are wanting to do this with film, I believe that I would do would be to do an enlarged color print of the size of the desired enlarged negative from my 35 mm negative. That would be the interpositive. From that color print, I would contact print my enlarged negative onto continuous tone film.

    The option would be to do this digitally. I know this is repulsive to some but it is an option.

  3. #3
    donbga's Avatar
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    Quote Originally Posted by philldresser
    I have a series of shots that I took on 35mm colour neg film which I want to enlarge onto B&W 5x4 neg film (or larger where necassary) for contact prints. I beleive I will need an inter-positive in the process but would love some advice.
    I have a 5x4 enlarger (inc 35mm inserts) and 5x4 film holders at my disposal.
    Any advice on what process, materials to use and what the pitfalls maybe would be gratefully accepted

    Phill
    Phill,

    Normally I don't disagree with Donald Miller but today I do. I don't see the utility in making the interpositive on color paper. Paper negatives really don't buy you anything, IMO. Instead make the interpositive onto panchromatic B&W film. FP4 or HP5 or Tri-X should work fine as long as the interpositive has a low CI. You can then enlarge on to lith film or another contone pan film for the final enlargement.

    Don Bryant

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    Quote Originally Posted by donbga
    Phill,

    Normally I don't disagree with Donald Miller but today I do. I don't see the utility in making the interpositive on color paper. Paper negatives really don't buy you anything, IMO. Instead make the interpositive onto panchromatic B&W film. FP4 or HP5 or Tri-X should work fine as long as the interpositive has a low CI. You can then enlarge on to lith film or another contone pan film for the final enlargement.

    Don Bryant
    My reasoning behind doing a print interpositive was that the color negative tonal scale will not replicate the actual color response of a print when it is exposed to panchromatic materials. If this were a color transparency then I would agree with Don Bryants recommendation.

  5. #5

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    Don
    Thanks for the replies. These are definitely colour negsnot slides.
    OK, I am a novice in this area, so how do you contact print the inter-positive onto film? Through the print?

    Phill
    It is not tradition that secures the survival of our craft, its the craft that secures the survival of our traditions.

  6. #6
    Bob Carnie's Avatar
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    Hi Phil

    If I read your post correctly you are trying to make an enlarged negative from colour negative.
    If so some options I would put forth.

    Kodak VPF film colour neg to colour neg - not sure if still made but commercial labs did do this in the past.
    LVT - black and white negative. output from scanned negatives, I believe you can go up to 11x14. Mr Callow has a good understanding of this process
    Enlarged digital negatives via inkjet seems to be popular.
    hope this helps

  7. #7

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    Quote Originally Posted by philldresser
    Don
    Thanks for the replies. These are definitely colour negsnot slides.
    OK, I am a novice in this area, so how do you contact print the inter-positive onto film? Through the print?

    Phill
    Phill,

    The way that I would try this is to expose the film to the same color scale that it would see if it were being exposed in camera. Now, one could do the same thing that is done with paper negatives (projecting through the paper support). However, in this case that would lead to an unsharp image. In this case, I would place the paper print side up and the film (emulsion side down) onto the print. In this case I would not use the normal film that I would normally use in the interpositive stage since it would entail projecting light through the antihalation layer and while that may be possible with lengthy exposures, I would rather use LPH film from Freestyle photo for both the interpositive and the enlarged negative. This film does not have the degree of antihalation coating that panchromatic film has. An additional benefit would be that this film is much lower in cost then pan film. For my developer, in this application, I would use Dektol at dilutions of 1-30 and possibly even slightly more dilute. This will allow a continuous tone interpositive from the normally high contrast film. I would project light through the interpositive film using my photo enlarger. On my Saunders, I would begin with exposures of approximately 45 seconds at F16 and development times of 1:30 to 3:00 min.

    You will need to test exposure versus development time to arrive at a flat contrast continuous tone interpositive. You should evaluate your interpositive on the basis that it contains density information in both shadow and highlight regions.

    When you have arrived at a low contrast interpositive, the next step would be to contact print this interpositve to an unexposed sheet of LPH film (emulsion to emulsion). This would then be your enlarged negative. The density range of the enlarged negative would be depending on what process you were wanting to print it on.

    I believe that this may provide an alternative to going the route of digital scanning and converting the continuous tone color negative to a continous tone enlarged black and white negative.

  8. #8
    Ole
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    Does anyone still sell Panalure, or Oriental Panchro?

    If you can find any of these make the interpositive on that...
    -- Ole Tjugen, Luddite Elitist
    Norway



 

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