Subject: Re: What happens to neg quality as dev becomes exhausted?
In article <firstname.lastname@example.org>,
> I want to shoot some resolution shots to test my LF lenses. If I use
> D-76 that has been spent developing other negatives, what can I expect
> from the negatives developed beyond the rated capacity? The qualities
> in a negative that the developer impacts are contrast, maximum density
> and accutance (maybe more?). I am guessing that as developer action
> declines, max density suffers, and therfore contrast. Could more
> frequent agitation or increased temperature help this? The point is
> avoid creating more water pollution for negatives that will never be
> printed, but if using old developer makes it impossible to judge the
> quality of the image, then it will not serve as a good indication of
> lens quality. Also, what is the dark precipitate seen in used developer
> that has sat for a while?
Generally as developer get used it has less active ingredients so it
takes longer to develop to the same contrast. There may also be some
effect from the oxidized developer by products left from previous uses.
Kodak used to give times for reuse of D76 without replenishment, perhaps
you can find them someplace. The problem is one doesn't really know how
much to increase the developing time with each use. Partly it depends on
how dense the prior films were.
If you want to conserve water want not replenish the developer. You can
buy D76R or mix it yourself. Another approach is to use a standard
developer like D76 diluted as a one shot. This way you always have fresh
developer for each batch.
Black stuff floating in developer is dissolved silver caused by the
silver solvent added to the formula to promote fine grain. It does no
harm, but can leave spots so it should be filtered out. If you have a
lot you should be using fresh developer.
Why spoil all your hard work and expensive film over a few cents worth
Robert D Feinman
Landscapes, Cityscapes and Panoramic Photographs
View All Messages in rec.photo.darkroom
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