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  1. #1
    JeffD's Avatar
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    Film curves and chemistry volume

    Typically I develop my 4x5 negatives in a jobo 3010 drum, rolling on a Beser print roller base.

    I have not done much experimentation in developing times to affect contrast, but am realizing that many scenes I photograph would benefit.

    Typically I use 50ml of solution per negative (500ml in my 10 negative drum)- my understanding is that at least 50ml of solution per neg will not become exhausted.

    My question:

    If I only have, say 5 negatives, or even 1 or 2, in the drum, and use the same volume of chemistry (500ml), will my contrast curves really change appreciably?

    I could understand that they would if I was using less than 50ml per negative, but will using more than that amount per negative reallly change things? If so, why?

    The reason I ask is sometimes I might only want to do one or two negatives at an non normal development time. If I only used the 50ml of solution for two negatives, it seems to me that, in the large drum, the negatives would not be in contact w/ the small amount of solution for as long a time, as the drum rolls. This would, in my mind, have an impact on the contrast curve.

    Thoughts?

  2. #2
    Loose Gravel's Avatar
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    This is similar to what I do. I have a 3006 drum. I always use the same amount of solution to get consistant agitation and exhaustion. If I don't fill all the holes with a negative (3006 takes 6ea 5x7), then I add one sheet of totally exposed junk film for every 2 open holes. So if I had 4 sheets in the tank, I would add one sheet of completely exposed film of the same size to one of the open holes.

    Does it change contrast if you don't do this? Yes, it could. Your developer would not be exhausting as fast. If you reduce the amount of developer, this would change your agitation. It depends on your film and your developer, etc. It is not always by some dramatic amount, but good darkroom technique depends on consistancy. Find a system that works for you and do it the same all the time.

  3. #3
    JeffD's Avatar
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    Thanks Loose,

    Glad someone else thinks about things like this! That is an interesting idea about 1 exposed neg for each two open holes. In theory, that should pretty much replicate having two normally exposed negatives as far as chemistry exhaustion.

    I guess I need to just test this. I would hate to have to use so many blank negatives, as I normally develop 10 in the tank, and would like, on occasion to develop only 2. That would leave me with having to develop 4 throw away negatives.

    If anyone has done any tests with a densitometer, that would show that "too much" developer would have a substantive impact, feel free to reply! You would save me an evening of testing!



 

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