makign a positive BW copy of a 35mm colour negative

Discussion in '35mm Cameras' started by RobertL, Nov 5, 2008.

  1. RobertL

    RobertL Guest

    I want to make some 35mm B/W slides from images on 35mm colour
    negative film. I pla n to use a slide copier lens on a normal camera
    and photograph the colour neg film onto ordinary 35mm BW film and
    process in the usual way. I should then get a positive image.

    has anyone done this?

    Are there any special exposure criteria that need to be considered or
    can I just expose the BW film as normal?

    many thanks for any comments.

    Robert
     
    RobertL, Nov 5, 2008
    #1
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  2. RobertL

    Peter Irwin Guest

    You will get very low contrast. Negative films developed normally
    have an overall gamma of around 0.6. The resulting slide will
    thus have much less contrast than the original scene.

    You will have some hope of a correct result if you shoot on
    a microfilm negative film.

    Peter.
     
    Peter Irwin, Nov 5, 2008
    #2
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  3. RobertL

    Peter Irwin Guest

    I think that all modern "source document microfilm" is panchromatic.
    Microfilm for making copies of microfilm often isn't. The stuff
    to look for is "source document" microfilm,
    Most of those seem to be sold with special low-contrast developers.
    You want something like Dektol or other paper developer to develop
    microfilm for making slides from negatives. My guess would be that
    5 minutes in Dektol 1:3 should be about right for typical microfilm
    if you want a gamma of around 3.0, but you will need to experiment.

    It may take some work to find someone who will sell a single 100
    foot roll of 35 mm perforated source document microfilm, but it
    is likely to be a pretty reasonable price when you do find it.
    I think the minimum order for colour print film is higher than
    that. I have a 2001 price list which shows a minimum order of
    two 3000 foot rolls for Kodak 2393 at $290.70 each, or six 1000 foot
    rolls of 2383 for $88.90 each. That's less than 10 cents a foot,
    but you have to buy a lot of feet. If Kodak will sell you a single
    1000 foot roll, it might be something most of us could manage.

    The black and white stuff (Eastman 5302) used to be available
    in 100 foot rolls cheap until recently. (I bought some direct
    from Kodak myself.) But it seems that as of Feb 2008, you need
    to buy 1000 feet minimum and that will set you back $117.70 according
    to the 2001 price list.

    Peter.
     
    Peter Irwin, Nov 6, 2008
    #3
  4. RobertL

    RobertL Guest

    Robert I'll try it with
     
    RobertL, Nov 6, 2008
    #4
  5. RobertL

    RobertL Guest

    oops, Sorry, hit the button before I was ready!

    thank you all for your comments. I might just try with one of the
    more contrasty BW films and see how it goes. Another route is to
    scan the negative and the nsend the digital image off to a lab.

    thanks

    Robert
     
    RobertL, Nov 6, 2008
    #5
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