Why C41 for BW

Discussion in 'Black and White' started by kris-bochenek, Oct 2, 2012.

  1. Please englighten me. I do my own BW developing with good results. I use Rodinal for developer and Ilford stuff for Stop and Fixer. Now I wanted to do some color film just to try it out, and see what I can get from my classic cameras. Now, when looking up some chemistry I cam across the video on Youtube that shows how to develop BW film in C41 and the author also mentions that same process can be used for color film. Why would you use C41 for Black and white? Is there a difference between "standard" process and C41? How is it possible that the same chemistry develops both BW and color?
     
  2. C41 is used to develop chromogenic black and white films. I'm not a big fan of them for reasons beyond the scope of this question. The C41 chemistry is much more expensive than typical black and white developers. The convenience factor of having your BW film developed at a one-hour place is the draw for some people.
     
  3. I'm not going to search YouTube for your particular video.

    You can't develop regular B&W film in C41, the blix will clear your image.

    There are "chromogenic" B&W films and papers that are designed for C41. They have a single layer with black dye
    couplers instead of three layers with cyan, magenta, and yellow. These are popular with people who want "real" B&W, but
    don't want to screw around with darkrooms. Ilford XP2 is probably the most popular. I don't know if Kodak makes T400 any
    more.

    Like any C41 emulsion processed in a commercial lab, don't bet on longevity. I've seen XP2 get hard to print after just 10 years, while Tri X does well 40+ years.
     
  4. On the plus side, chromogenic B&W is easier to scan than silver film. The DMAX is closer to what a scanner likes, and
    infrared dust and scratch eliminators like Nikon's ICE work on them,
     
  5. chromogenic B&W paper?
    using color chemicals for paper? to make B&W prints.
    would this be a "sort of" replacement for panalure ?
    ( panchromatic enlarging paper)
     
  6. The grain structure (well, dye cloud structure) of Kodak BW400CN and Ilford XP2+ is distinctive. Very smooth look for a 400 speed B&W film. Also wide latitude, particularly for overexposure. There are legitimate artistic reasons to use it.
    But, mostly, it's so a mini-lab can process and print it without really knowing what they are doing.
     
  7. so is it purley to do BW without using dedicated black and white developer? Doesn't this limit you in the selection of BW films?
     
  8. Kris Bochenek [​IMG], Oct 02, 2012; 02:50 p.m.
    so is it purley to do BW without using dedicated black and white developer? Doesn't this limit you in the selection of BW films?​
    Yes, you are limited to two films, Kodak BW400CN or Ilford XP2. As everyone has said, the advantage is that you can take it to a minilab and get B&W prints from it. Normal minilabs can not develop non-C41 black and white film.
    So let's say you're an arsty-fartsy 20-something who wants to look cool, so you want to shoot black and white FILM because digital is passe and color is no longer hip. You have no darkroom access, skill, nor knowledge. You try a roll of Tri-X but the local minilab says they can't process it. Somehow you find out about the C-41 film and viola! You are now hip, retro, and cool.
    Alternatively, you might just like the way the film looks and prints. I do. Even more, I ADORE the way it scans.
    On the negative side, trying to actually print it is a real pain. The Kodak variety has the typical orange mask you see on color negatives, and the Ilford stuff - well, better printers than me get good results with it. I cursed it a lot. I have tried printing the Kodak variety on color paper in my darkroom and it's hard as heck to get a print with a neutral tint.
    Grab a roll of the Kodak at Walgreen's. Get it printed at your local minilab. You may, or may not, see what all the fuss is about. Realizing of course that any "fuss" with film, nowadays, equates to one guy rooting for the Red Sox at Yankee Stadium.
     
  9. As you know, black & white film is constructed by coating a light sensitive layer on film base. This layer called an emulsion consists of salts of silver imbedded in a gelatin binder. When exposed, a chemical change takes place making the silver salts suitable for reduction. The developer is a reducing agent that is able to distinguish exposed vs. unexposed silver salts. The developer reduces the exposed salts and, for a time, ignores the unexposed. In this case reduction splits the silver salt crystal into its two component parts. Metallic silver, which remains imbedded in the emulsion, and a halogen. It is the metallic silver that forms the image; the released halogen is dissolved by the waters of the developer. Unexposed silver salts remain and after a time will reduce if the film is allowed to remain in the developer for an extended time.
    Color films such as C-41 and E-6 are also constructed by coating light sensitive layers on film base. Additionally, imbedded in the emulsion, are incomplete dyes. The color developer acts much the same as a black & white developer except the color developer, as it reduces the silver salts, also supplies the missing dye ingredients. As the metallic silver emerges, it becomes a catalyst that allows the incomplete dye to unite with the missing dye ingredient. Thus a black & white image and a colored dye image are simultaneously formed.
    The colored dye image is translucent whereas the silver image is opaque. The sliver image veils the color image, therefore, it must be removed. An ordinary fix solution will remove unexposed and thus undeveloped silver salts. However, the fix is not a solvent for metallic silver. The bleach solution attacks metallic silver and converts it to a compound soluble in ordinary fixer. Once bleached and fixed, all traces of the metallic silver image are removed. Now the colored dye image blossoms to reveal the color image.
    Because black & white films and color films have common origins, it is possible to cross develop to achieve some artistic goal. Most cross developing techniques have their origins in rescue procedures. Human error in the darkroom sometimes resulted in cross processing. As an example, color films processed in black & white solutions can be re-bleached and re-developed. Most often cross processing and the rescue technique yields a substandard result, however, one person's boo-boo can be another person's treasure.
     
  10. Perhaps you saw that backwards. You may have seen C-41 developed in B&W chemicals, in which case this is totally doable. Interesting, but doable. As someone has mentioned here before the blix process in C-41 would erase a B&W image. If I remember correctly, developer, is developer, is developer. (Generally speaking).

    I cross process C-41 in B&W chems all the time. Mostly because my local lab gives me free film that's generic fuji every time I bring in some Kodak Gold, and because I have to order my B&W film online. So, for me, it's more a situation that 'Hey! I have chemicals going to the bad. Hey! I have film I'll never 'pay' to develop...Let's shoot the cat!' It's a novelty thing really. (And a great way to prove my fixer still works!)
    If you do develop C-41 in B&W they will not be in color. They will be flat and pretty darned dense. Occasionally you get really lucky and get some awesome looking shots. Unless you're like me and develop them for ten minutes in eighty degree developer. Meaning careless. Most of them will need to be scanned and digitally corrected.

    C-41 black and white is really fun stuff. It has a nice buttery look to it that I find charming. Sometimes when you're doing something like a fashion shoot or wedding photos you want a smoother grain than conventional black and white. I suppose it would be a challenge to print though. I never done it as I do not have the room for an enlarger.
     
  11. Thank you all for nice way you explained this to me. The video did mention XP2, but I didn't realize that BW film had more versions than just BW. Now I know more. I still want to try my hands on color film shot on my classic "babies" but maybe sending the rolls out to Dwaynes is my better option.
     
  12. I've shot some 120 XP-2 and made some darkroom prints. No problems at all. Prints looked great.
     

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