C-41 b/w films

Discussion in 'Darkroom Developing and Printing' started by David Clarkson, Jul 19, 2003.

  1. I have no experience with color films so I'll need some assistance working
    my way through a question about Ilford XP2 Super, Kodak Portra C-41, and
    Kodak T400 CN.

    I would like to use these films in those situations when I cannot develop my
    film myself. I have some experience with XP2 and have found it satisfactory
    but I have not asked much of it yet.

    My issue is how exposure compensation will effect the film. I typically
    shoot b/w films with more exposure than recommended by the manufacturers and
    typically underdevelop for acceptable detail and contrast (my "normal").

    What effect, if any, will exposure compensation have on these films when
    developed at a commercial C-41 processor? (I assume that I cannot request
    any non-standard development process from these commercial processors.) Can
    I at least manipulate the exposure to achieve similar results with this

    David Clarkson
    David Clarkson, Jul 19, 2003
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  2. David Clarkson

    Mark A Guest

    If you do your own printing or scanning, you should use XP2 or T400CN. Porta
    is designed to make B&W prints on color paper with an automated color
    processing machine (it has a orange tint like color film).

    The "advertised" speed rating of these films is 400, but that is not the
    true ISO rating using foot speed. Read the data sheets for details. Most
    people recommend using 200 speed for best results (including Ilford and

    Custom labs can push C-41, but unless you need more than ISO 800 speed,
    pushing is not recommended for best results. Very few (if any) one hour labs
    will push C-41. Make sure that the lab knows it is a C-41 film (lots of high
    school kids work at these places).

    Most people think XP2 is the better of these films for conventional B&W
    printing or scanning.
    Mark A, Jul 19, 2003
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  3. I think you'll like the results. C-41 films become finer-grained with
    overexposure. They do not block up. Many people expose them somewhat more
    than the speed rating indicates.

    Also, they tend to have fairly low contrast and a very long tonal range in
    the first place -- just the effect you achieve with ordinary film by
    exposing generously and underdeveloping.
    Michael A. Covington, Jul 19, 2003
  4. David Clarkson

    Mark A Guest

    That's because the "speed ratings" are bogus and not based on the ISO
    standard of using foot speed. This is stated in the Ilford fact sheet for
    XP2. Both Kodak (for T400CN) and Ilford (for XP2) recommend 200 speed for
    best results

    For Porta, you can verify the 200 speed rating by looking at the Kodak Data
    Sheet for T400CN where is gives exposures for various lighting conditions,
    and the T400CN exposures are 1 stop more than other 400 films. Curiously,
    Porta 400 B&W (for use in a color processing machine with color paper) is
    recommended to be used at 400 speed.
    Mark A, Jul 19, 2003
  5. David Clarkson

    John Guest

    And never have been.


    John S. Douglas, Photographer
    ( NOT an ISO 9000 site ! )
    John, Jul 25, 2003
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