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  1. #31

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    Quote Originally Posted by Kirk Keyes
    Does this really happen, Sandy? I've never tried changing developer concs, just time. Why does the B+F not increase proportionally to the contrast index, regardless of the time it takes to generate a given contrast? Afterall, higher strength developer will be more active so it should build fog levels faster than a lower strength developer given the same amount of time. Maybe you have some data to demonstrate this?

    THanks - Kirk
    Based on empirical expereince I say it works pretty good. This was my favorite way of working with Tmx RS and Tmx 100. I used 1:15 for n-2, 1:9 for normal and 1;4 for N+2 all developed at 9 min at 72 ºF. I must say the fog levels were very low for the 1:4 solution. Of course this was done for silver printing, and I have not tried it with pyrocat nor am I likely to try it, I tend to stick with what works for me. So low fog levels for higher concentrations of pyrocat might not be the case, but it is worth a shot and experiemnting.

  2. #32

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    jdef wrote, "It seems to me that a dilute solution's activity would be progressively reduced by oxidation, extending development times, and increasing general stain."

    So Sandy (0r others, I guess), is this more an issue/effect with staining developers then, or as Jorge indicates all developers?

    Kirk

  3. #33

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    Quote Originally Posted by jdef
    I would think that if the oxidation product of a developer causes fog, then the same principles would apply. It would seem especially important in a staining developer, but perhaps not limited strictly to them.

    Jay
    But will not unoxidized developer generate fog as well? Hence my suggestion that more concentrated developers will increase fog too?

  4. #34

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    Quote Originally Posted by Kirk Keyes
    But will not unoxidized developer generate fog as well? Hence my suggestion that more concentrated developers will increase fog too?
    Time is also a factor in the development of B+F stain. If you can develop the film to the desired CI in 12 minutes in a strong solution you will have less general stain than if you develop the film to the same CI in a very weak solution for 45 minutes, assuming symmetrical parts of Solution A and Solution B. For example, I have observed that for the same CI I get more B+F stain with long development and weak solutions (as with stand and semi-stand development) than with rotary development and strong solutions. That is why I have recently started to recommend an asymmetrical ratio of about 3:2 A:B when long development times are required as this reduces B+F stain. One of the things that surprised me intially with semi-stand development is that the developer is virtually clear after development, with no hint of oxidation, but nevertheless, B+F stain is fairly high. Why is that? I am not entirely sure but part of the answer appear to be simply that the film was in contact for a much longer period of time with developer by-products.

    However, regarding many of the specific questions raised here I really am not sure of the answer and am simply speculating. I will try to test the concept sometime in the near future and will let you all know what I find.

    Sandy
    Last edited by sanking; 01-26-2005 at 09:50 PM. Click to view previous post history.

  5. #35
    Ole
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    This concentration/time/oxidation/fog thingy fits in well with my experiences with other (improvised) staining systems.

    I needed to intensify a negative, and did a bleach and redevelop. The redeveloper was one teaspoon pyo, two teaspoons potassium carbonate, one liter water. Stain was massive, so was base fog. Developent ended when the developer died - it was nearly black by that time.

    Another version was a negative I realised was underexposed (for Pyrocat-HD) and needed lots of shadow detail (don't ask...). First development for four minutes in Neofin Blau, then eight minutes in Pyrocat-HD 2:1:100. Good shadow detail, very high base fog, and a fully usable negative!
    -- Ole Tjugen, Luddite Elitist
    Norway

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