Controlling Contrast in Colour C-41 --> RA4 Printing

Discussion in 'Darkroom Developing and Printing' started by Alan Smithee, Aug 24, 2005.

  1. Alan Smithee

    Alan Smithee Guest

    I'm starting to set the gears in motion for adding colour to my darkroom and
    it got me thinking. How does one control contrast changes in C-41 --> RA4
    color printing? Is it done in paper or filtration. Given (I'm told) one
    shouldn't alter the contrast (why?!) when processing the film, what "grade"
    does C-41 film aim for? 2 or 3? Thx.
     
    Alan Smithee, Aug 24, 2005
    #1
    1. Advertisements

  2. Alan Smithee

    David Starr Guest

    Per the instruction sheet packed with the Tetenal C-41 chemistry I use, you can
    increase the contrast "somewhat" with extended development - about 15 seconds,
    IIRC. Different papers can change contrast a little, too. Kodak's Portra
    papers are a bit lower in contrast and saturation than the Supra papers. I've
    gone from one paper to another to get a slightly different "look" from the same
    negative, but generally, I don't worry about it.

    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    Retired Shop Rat: 14,647 days in a GM plant.
    Now I can do what I enjoy: Large Format Photography
    www.destarr.com
    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     
    David Starr, Aug 24, 2005
    #2
    1. Advertisements

  3. Alan Smithee

    Ken Hart Guest

    You can get a bit of contrast increase by increasing C41 develope time by
    :15 to :30 (develope time is 3:15).
    The only filtration done in printing is for color balance, not contrast.
    There are different contrast grade papers: Kodak's Pro Endura series comes
    in Portra, Supra, and Ultra, three different paper contrasts. I use the
    Supra, medium contrast.
    Color print films have different contrasts. _Generally_, consumer grade
    films are more contrasty than pro type films. The story I've heard is that
    the higher contrast is to make up for the typically poorer lens of the Point
    & Shoot cameras.

    Experiment and take notes. Eventually, you will find a film and paper
    combination you like. Then the manufacturer will discontinue it!
     
    Ken Hart, Aug 25, 2005
    #3
  4. Alan Smithee

    nailer Guest

    contrast is a feature of a film, you do not alter/manipulate it during
    c41. there are films dedicated to portrait, wedding, industrial,
    landscape, fashion etc.
    RA4 does not alter gamma of a paper, and the paper comes in one fit
    all size. various papers have different specs, gcontrast to some
    extent too.

    On Wed, 24 Aug 2005 21:53:03 GMT, "Alan Smithee"

    *I'm starting to set the gears in motion for adding colour to my darkroom and
    *it got me thinking. How does one control contrast changes in C-41 --> RA4
    *color printing? Is it done in paper or filtration. Given (I'm told) one
    *shouldn't alter the contrast (why?!) when processing the film, what "grade"
    *does C-41 film aim for? 2 or 3? Thx.
    *
     
    nailer, Aug 25, 2005
    #4
  5. Kodak - Portra, Supera and Ultra papers have varied levels
    of contrast. One can to a degree control contrast by paper
    selection. As far as adding contrast to the image aside from
    paper selection your right.
     
    Gregory Blank, Aug 26, 2005
    #5
  6. When printing, you can increase color saturation (and thereby contrast?) by use
    of the Anderson Method. Quoting myself from a post back in 2001:

    The technique is described in the booklet "Perfect Color Printing" from
    Photo Techniques Magazine. It was stated there for the EP-2 method, but
    I have successfully applied it to RA-4 chemistry.

    Here are the steps:

    1. Expose as normal
    2. Develop in color developer as normal
    3. Fix in B&W fixer for 2 minutes
    4. Wash thoroughly
    5. Bleach in 2.5% solution of potassium ferricyanide (w/ 7g potassium
    bromide) for 2 minutes +
    6. Wash thoroughly
    7. Redevelop in color developer
    8. Either repeat from step 4 to further increase saturation or use
    bleach-fix as normal
    9. Wash and dry.

    The reason it works is explained by Dr. Chapman in his article "The
    Photochemistry of the Anderson Method" contained in the same booklet.
    There are always unused color couplers in conventional color emulsions.
    Recycling the silver halides allows the activation of further color
    couplers from the appropriate dye layer.


    Francis A. Miniter
     
    Francis A. Miniter, Aug 26, 2005
    #6
  7. Alan Smithee

    Alan Smithee Guest

    It seems the development of C-41 was aimed more at retailers of photo
    services and not to those who wanted to do colour in the darkroom. Was C-41
    really the best solution. Was it a product of evolution or marketing on
    Kodak's part? Why is/was it so hard to make a colour film that could change
    contrast with development?
    I don't know enough about the history of colour film at this point. Is it
    any easy to control contrast with slides or do they also have the same
    problem? Thx.
     
    Alan Smithee, Aug 26, 2005
    #7
  8. The film has the longest tonal scale of any color product. :-D Ha that
    should start a religious war.

    Both--- as are all items ever made and sold. The interesting thing is
    C41 is derived from the motion picture industry (I seem IIRC)...
    someone told me once they made the positive by contact exposure
    of film to film in a special apparatus for doing so....Maybe Richard K
    knows more and will correct any errors I may be quoting :)

    Color shifts.---- Slide film shifts color also, but mostly its not the
    cross over shifts you see in C41 process modification (In My
    experience). Its an interesting question though.

    You can adjust contrast by pushing or pulling slide films, again the
    color will shift slightly warmer for pushing & cooler for pulling. You
    can not vary the the push or pull as much as B&W negatives and still
    have a result beyond clear or opaque film.
     
    Gregory Blank, Aug 26, 2005
    #8
  9. Alan Smithee

    nailer Guest

    -----------------------
    *It seems the development of C-41 was aimed more at retailers of photo
    *services and not to those who wanted to do colour in the darkroom. Was C-41
    *really the best solution. Was it a product of evolution or marketing on
    *Kodak's part? Why is/was it so hard to make a colour film that could change
    *contrast with development?
    *I don't know enough about the history of colour film at this point. Is it
    *any easy to control contrast with slides or do they also have the same
    *problem? Thx.
    *
    unlike BW film, in color neg film you have to balance three layers, it
    is difficult considering many factors involved.
    c41 was introduced for technical, economic and environmental reasons.
    Home processing is not profitable.
     
    nailer, Aug 26, 2005
    #9
  10. Alan Smithee a écrit :
    C-41 and E-6 are standardized processes not meant to have contrast
    control, no the way we can do in B/W.
    But, if you want prints from slides, Ilfochrome is available in various
    grades. You can also influence contrast by modifying the chemicals used
    (P-30 contrast is lower than P-3 and some home-made developer formulas
    give also more/less contrast).
    BTW, Ilford announced new P3.5 chemicals kit, all liquids for 5 liters,
    replacing the 2-liters P-30:
    http://www.ilford.com/html/us_english/ILFOPRO/forum/topic.asp?TOPIC_ID=6763

    The best contrast control, like for graded papers, is acheived by
    masking techniques from simple dodging/burning to advanced silver masking.
     
    Claudio Bonavolta, Sep 2, 2005
    #10
  11. Alan Smithee

    UC Guest

    UC, Sep 2, 2005
    #11
  12. E6 although not specifically designed perhaps to be pushed and pulled
    can readily be done so.
     
    Gregory Blank, Sep 3, 2005
    #12
  13. Gregory Blank a écrit :
    Yep, but there are several other aspects in pushing-pulling than just
    contrast variation (grain, color balance, ...) that makes it not always
    suitable for contrast control.
    I do prefer other methods that keep all other characteristics of the
    film and adjust only the contrast.
     
    Claudio Bonavolta, Sep 3, 2005
    #13
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.