What you suggest is given as the recommended method for many modern
developers, for instance T-Max RS and Xtol. I think it would work for
either D-76 or DK-50 provided the correct amount of developer was
replaced. For any replenishment system to work you really should
establish the rate of replenishment by sensitometric means but that is
over kill for most of the sort of work we do. For photofinishing (does
it exist any more?) or motion picture processing it is essential but
probably not for small home labs. I think the reason the replenisher
formulas have a lot of alkali in them is to compensate for the
accumulation of bromide and iodide in the developer. However, while
average density and film speed can be held fairly constant the shape of
the film curve may change as it does when more restrainer is added. I
need to find my copy of Haist's book because I think he deals with this.
Its in storage (I think I know where) and I hope the silverfish haven't
gotten to it.
On 7/14/2017 7:45 AM, Tim Daneliuk wrote:
When dealing with D-76 or DK-50, is it really urgent that one use the
replentisher chemistry? Why can't I just use fresh devloper (at the same
dilution) and top up the working developer with, say, 1oz of fresh dev
every use?
