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  1. #1

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    35mm enlarging - stain masks with Pyro?

    Hello. This relates to enlarging 35mm negatives with difficult highlights that cannot be burned in precisely using the usual methods, and where flashing would be detrimental.

    Masking can often be quite helpful with this sort of situation. I've been working recently on "perfecting" some masking techniques for small format films (based on the typical large format procedures but scaled down and altered slightly). They are pin registered and sandwiched in printing.

    Most of the masks I find useful are burn masks (or dodge masks depending on how you think about it) exposed/developed to put a relatively small amount (say a stop or two) of essentially featureless (as much as possible) density everywhere except in the brightest highlights which are clear. A potential variation on this occured to me and I wanted to run it by the forum for comments.

    A typical Pyro negative from say PMK, has greenish imagewise stain which acts as a variable density low contrast filter in highlight densities when printing on most VC papers. This can sometimes help to bring in subtle highlight detail if the flattening effect is not too pronounced. However, I don't like Pyro with small format negatives. They are just too grainy for me for most subjects. So how do I combine the PMK stain with a solvent developer like XTOL? Well, what if I took the XTOL image negative, made a mask in my usual way, and then continued with this:

    1. Use first mask as an interpositive to make a second mask (a "negative" mask)
    2. Develop the negative mask in Pyro
    3. Bleach away all the silver in the Pyro mask

    The Pyro mask would be mostly featureless film base, but with some green stain in the highlights. When sandwiched with the original negative, the highlights would print as though they had some amount of #00 filtration built in. Obviously this would require quite a lot of trial and error in exposure and development at every stage.

    The main issue I'm stumbling on in these initial thought experiments: Although the Pyro mask would add only "color" density to the highlight silver densities in the original negative, in the end would this additional printing density more than offset the contrast filter effect and actually worsen the entire situation?

    Other issues/thoughts I'm going in circles on:

    -I've never bleached all the silver out of a Pyro negative. What does the remaining stain look like, say under a grain magnifier? Is it just smooth dye coloring?
    -Suppose you use something like Wimberley's instead of PMK, and you get more of a yellow-orange stain?

    Thanks
    Michael

  2. #2

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    Since no one else is responding to this, I'll chime in.

    First, the assumption that you are making about pyro stain acting as a "variable density low contrast filter" may not be true. This very issue has been discussed here at length (do a search). I was originally of the same opinion as you, but Nicolas Lindan, who probably knows more than any of us about pyro stains, has about convinced me that the color of the pyro stain is roughly equivalent to a grade 2 filter and does not have the effect of changing contrast appreciably between low and high values. So, what you have is a "variable density grade 2 filter" which may make some difference when printing with very high and low contrast filters, but otherwise will only have a small effect, if any. Although pyro negs may print differently on VC and graded papers, the differences in paper formulations, etc. prevent one from firmly attributing contrast differences to the pyro stain. Constructing a test for this is problematic.

    What the stain does is add density that helps mask grain. If you make a mask as you describe, the pyro stain density would simply add to the density already in the negative, giving you more contrast, not less. I think you would be better off with a regular contrast-reducing mask than bothering with the pyro stain mask. If you do want to try the pyro stain mask, make a first-generation contrast-reducing mask, develop it in pyro and bleach away the silver. This will at least give you contrast reduction instead of an increase.

    There are other techniques, which you are likely aware of that may help as well. You mention flashing, but seem to feel that the compression of values in the highlights is not appropriate for the goal you have in mind (however, this is precisely what you seem to be after with your "variable density low contrast filter"). Nevertheless, I find that small amounts of flashing in conjunction with other techniques quite helpful at times. Then, there are reduction techniques for the negative itself. These are irreversible, but have worked for many (I tend not to use them).

    Another technique to explore is the "New Sterry Method," in which paper is bleached with weak dilutions of ferricyanide/bromide before development. This changes the contrast in the shadows and leaves the highlights mostly untouched. It works well and may be the thing you are looking for. I believe Unblinking Eye has some articles on this. A Google search will turn up lots of info.

    FYI, bleaching the image silver from pyro negatives is easy. Just use a rehalogenating bleach of ferricyanide and potassium bromide. I use 20g potassium ferricyanide and 8g potassium bromide to 1 liter of water (or equivalent. The bleach can be reused.). I do this in conjunction with redevelopment in a pyro developer to add more proportional density (contrast) to a weak negative. The silver redevelops and more pyro stain is added, which gives the extra contrast. This is likely not suitable, however, for smaller-format negs, since the redevelopment changes the granularity of the negative. With LF negs, the effect is less noticeable.

    Finally, however, the question arises as to why you are not simply working to get better-developed negatives that print better at normal contrast and don't need the kind of extensive masking you are doing. If you find you need to do a lot of masking to just control contrast, then maybe you should be developing less... Just a thought.

    Best,

    Doremus Scudder
    www.DoremusScudder.com

  3. #3

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    Hi Doremus. Thanks for the feedback on this. The more I think about it I agree the Pyro mask is not likely to work, and as you say, it could even add contrast. I also agree that controlled flashing can often be used in subtle ways without too much flattening. I was just trying to think out loud about alternatives. But creating the pyro mask (if the stain even ended up doing what I thought it might do) would be exceedingly difficult as I think through each step. So basically the more I thought about it I come to the same conclusions as you.

    Regarding development of the original negative, I want to clarify that this thought pertained only to certain (not all) extreme contrast cases, where I try to think about other ways of getting to the final print besides compensating development. So this would fall outside the normal methods of zone system control on the contraction side. I'm able to control these negatives, but just thinking about other possible ways of doing things. Sometimes compensating-type procedures can just end up making things harder due to excessive flattening of values, so occasionally relatively subtle masks can help. Since with practice they can be made to act on specific areas or values, it is sometimes better, even under extreme conditions, to opt for a more mild contraction in the negative.

    My interest in masks is limited to this type of situation, so it's not what I would call a standard part of my wokring procedures, just another tool in the box that might help here and there. I'm definitely not trying to put unsharp masks on all my negatives. It's not my cup of tea. But the occasional burn/dodge mask can help.

    Thanks again for the response. This is exactly the type of feedback I was hoping to get . I think for now this experiment will go on the back burner.

  4. #4

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    My limited experience is that the pyro stain does not have much effect on print contrast, except, perhaps, when contact printing with UV light. Pyro developers get pretty fussy and are often unpredictable, but I think an modern formula, like Pyrocat HD, might give quite good results with 35mm. I've only tried it with larger formats. The usual masking technique relies on somewhat unsharp masks, with the mask separated from the emulsion by the film base. That will also hide a good deal of any grain. The Steary process is a definite possibility, although I haven't tried it. I have no reference for the "New Steary Process" (help, anyone), but an old formula is:

    Steary Process

    For use when the negative scale is too long for the paper and no softer grade is
    available.

    Water 750 ml
    Potassium dichromate 100 g
    Ammonia (0.880) 10 ml
    WTM 1 l

    For use, dilute 4 to 12 ml of the stock solution to 1 liter for contact papers, 12 to 20 ml per liter for enlarging papers. Exact dilution depends on the paper used and the effect desired. Expose the paper sufficiently to bring out the highlight detail, regardless of overexposure in the shadows. Immerse exposed paper in the above restraining bath for 2 to 3 minutes, rinse in running water, then develop normally. If the bath is too strong or is used for too long a time, the print color will be poor.

    A related process from 1881 is Eder's harmonizing reducer. It was used directly on the (large) negative and, thus, may not be desirable.


    Harsh negatives can be "harmonized" by reducing the higher densities and intensifying the lesser densities.

    Hydrochloric acid 30 ml
    Potassium dichromate 10 g
    Potassium alum 50 g
    WTM 1 l

    Bleach the negative completely. Wash out the bleach stain. Redevelop in a slow acting developer, such as an M-Q developer diluted 1:4. Develop until shadows and midtones are correct. Fix and wash as usual. (DuPont recommended using D-25 diluted 1:5 as a redeveloper.)

    Variations: these alternative bleaches have been proposed:

    Chromic acid 5 g
    Potassium bromide 10 g
    WTM 1 l
    Use as above.

    Potassium bromide 5 g
    Cupric sulfate 5 g
    WTM 1 l

    Redevelop in metol and wash (fixing not needed).

  5. #5

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    The new "Sterry" process:

    http://www.davidkachel.com/historical/nw_strry.htm

    Check out the other fine articles on David Kachel's site as well.

    Best,

    Doremus Scudder
    www.DoremusScudder.com

  6. #6
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    Quote Originally Posted by Michael R 1974 View Post
    The main issue I'm stumbling on in these initial thought experiments: Although the Pyro mask would add only "color" density to the highlight silver densities in the original negative, in the end would this additional printing density more than offset the contrast filter effect and actually worsen the entire situation?
    It depends on the color of the stain and the sensitivity of the paper. For example, when using Ilford multigrade paper, blue light affects density in shadows more than the highlights. Therefore, a yellow stain in the highlights of your projected negative will not have much effect on the highlights, if that is what you are asking. But if the yellow stain is in the shadow area, it will have considerable effect. If you stain the whole thing yellow that will 'hold back' the shadows. Another, easier, way to do it is to just put a yellow filter in the light source when printing.



 

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