Chromium intensification / cut film / re-development

Discussion in 'B&W: Film, Paper, Chemistry' started by bernard_L, Jan 11, 2014.

  1. bernard_L

    bernard_L Subscriber

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    I have several films (135 and 120) that were developed at too low contrast. They need grade 4 at least, leaving little room for manipulation. The reason(s) why they turned out too low contrast is not the topic.

    I have ordered the chemicals to prepare chromium intensifier. The issue is that the films have already been cut in strips for storage. I intend to insert them in reels for intensification processing.

    First question is about drying. Either dry each strip, hanging from one corner (I have some mini-clips with just one tooth) with a second clip pulling from the opposite corner. Fairly easy with 135 (perforations); a little tricky with 120. Once dry, put away to flatten for a few days. Alternate method is to dry them while still on reels. Positive: no tricky manipulations, controlled curl, only lengthwise. Negative: risk of drying marks or worse, gelatin adhering to the reel, especially with 120, where the image edge is close to the film edge.
    Advice from members with actual experience is welcome.

    Second question. I need to gain the equivalent of 1 to 1.5 paper grade. I see that the amount of HCl in the working strength bleaching solution can be between 2.5 and 12.5cc for 1000cc. With the lesser amount giving more intensification. Could someone provide a starting point, in view of my goal of 1-1.5 paper grade intensification? Of course I'll use non-keeper frames for preliminary tests, but some indication would be welcome.

    Third question. I have read that re-development should be with a developer with low sulfite content, with Dektol 1+3 suggested. I'm also concerned about grain if re-deloping in Dektol. In view of these concerns, is there any advantage in preparing a custom developer with even less sulfite? Say, take D-76 and decrease sulfite to, say, 50g, or whatever?

    Thank you.
     
  2. ParkerSmithPhoto

    ParkerSmithPhoto Member

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    Try selenium 1:1 on a spare piece of film. It can work wonders to boost contrast. This is a favorite of John Sexton.
     
  3. Rudeofus

    Rudeofus Subscriber

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    The main question I would ask myself: is printing at grade 4, or even 5 so much of an issue that it warrants a procedure with toxic chemicals and possibly some loss in image quality? I'm all for experimenting and learning, but risking perfectly printable negatives to some mostly procedural improvements ...
     
  4. Gerald C Koch

    Gerald C Koch Member

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    Selenium is not going to give you the density you need. With luck you can get 1 paper grade.

    Use a tray and do one strip at a time. You need to see what you are doing during the process.

    Any intensifier is going to increase the grain a bit. One is trying to obtain a usable negative. Like so many things in photography you can't have both.

    Chromium intensification can be repeated more than once. If desired the last intensified image can be toned with selenium for greater density and permanence. Some people use a staining developer rather than a print developer.

    First test the process on a negative that is not valuable.
     
    Last edited by a moderator: Jan 11, 2014
  5. David Allen

    David Allen Member

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    I would suggest that you try the following:

    Film:
    Selenium tone one strip of film (5 – 10 minutes) - this is much less risky than intesification

    Printing:
    Use Dokumol diluted 1 + 6 and develop for AT LEAST 3.5 minutes

    If you can't get hold of Dokumol then mix up your own Ilford ID-55 and use at 1 + 3:

    Metol . . . . . . . . . . . . .. . 2 g
    Sodium Sulphite anhyd . . 40 g
    hydroquinone . . . . . . . . 12.5 g
    Sodium Carbonate . . . . . 72 g
    Potassium Bromide . . . . . 1.5 g
    Water to . . . . . . . . . . . . 1 litre

    Combining the Selenium toning of the film with either Dokumol or ID-55 for the prints will give you an effective increase of contrast of +1 grade.

    Bests,

    David
    www.dsallen.de
     
  6. bernard_L

    bernard_L Subscriber

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    Thank you to all who took the time to respond so far.
    I had tried selenium before and got a minimal increase of contrast. Plus, once toned, that's final. See reply by G.Koch.
    Printing on grade 4 (or 5, which would more properly called 4.5, at least for Ilford Multigrade; look at their published curves) leaves no room if I need to, e.g. burnin shadows at higher grade to give them punch.
    ID-55 don't know, but I have already tried ID-14 and got maybe 1/2 grade gain at most. Dokumol I can buy, sure, but I would rather use it to rescue old paper (combined with benzotriazole).
    Regarding grain increase associated by intensification. Experiment will have the final word, but Barry Thornton states that, contrary to a commonly stated opinion, the way to have prominent grain is to develop to a low contrast and print using a high grade paper, rather than the opposite (for equal final contrast).

    As it happens, between the original post and now, I received Fred Picker's Zone VI Workshop. Quoting from top of page 1:
    Accordingly, I'll try intensification (selenium alone, chromium followed by selenium) of the negative before trying to squeeze a true grade 5, or more, out of Multigrade. You might say that to follow Fred Picker's advice fully, I should shoot again the pics. Most of them are northern Chile, 14+2 flight hours from here.
     
    Last edited by a moderator: Jan 11, 2014
  7. pgomena

    pgomena Member

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    I've never had great success with bleach/redevelop intensification on small format films. It's always a last-ditch effort to save an image. Selenium does work, but it will only give you about 1 grade of contrast increase, as others have said.

    One suggestion before you reprocess your irreplaceable tiny 35mm images: Scan them. A decent scanner can do miraculous things with a thin, flat negative. Once you've saved your images in digital form, have at it with the intensification process, and good luck.

    Somewhere on this forum is the suggestion to bleach thin negatives, expose them to light, and reprocess them in a staining developer to boost contrast. If more contrast is needed, selenium intensify the stained negatives.
     
  8. Ronald Moravec

    Ronald Moravec Member

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    Victors intensifier. Add contrast, remove with fix. Components maybe difficult to obtain but it works a treat.
     
  9. Gerald C Koch

    Gerald C Koch Member

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    Also extremely poisonous and not considered archival.
     
  10. David Allen

    David Allen Member

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    This is because you need to use it much stronger than for archival treatment of a print.

    Why? "to rescue old paper" – your stated problem was to increase contrast and this is exactly what Dokumol and Ilford ID-55 will give you.

    Bests,

    David
    www.dsallen.de
     
  11. Jim Noel

    Jim Noel Member

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    Selenium will not give you as much increase as you want. Chromium INtensifier will add to your grain and is very toxic to the environment.

    Sepia tone the negatives to gain 1.5-2.0 zones increase in the highlights, thus increased contrast. This can be done with the lights on and the redevelopment can be done with your favorite developer.
     
  12. Gerald C Koch

    Gerald C Koch Member

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    It is chromium (VI) that is very toxic. Mixing the used bleach with sodium sulfite will reduce the chromium to chromium (II) which is an essential trace element. Add sodium sulfite until the orange color changes to green.
     
  13. bernard_L

    bernard_L Subscriber

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    Thanks again for the responses. As it happens, I have in my pending order for chemicals also thiourea. So, will try Chromium versus Thiourea (aka thiocarbamide) toning. And make sure I reduce the Cr(VI) with sodium sulfite before disposal. Maybe I'll post the results in a new thread.
     
  14. Rudeofus

    Rudeofus Subscriber

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    You can increase print contrast by applying subproportional reducers after the process. This gives you plenty of room for experimentation and optimization without any risk to your negs.
    I have made the observation that modern multigrade papers, assuming full development, don't respond much to changes in developer composition. Given that, I'm surprised you saw any difference at all.