Re: [Leica] Development question

[Martin Howard <mvhoward@mac.com>]

On Wednesday, Jul 2, 2003, at 11:19 America/Los_Angeles, Mark Rabiner 
wrote:

> Martin that happens with some developers when you have diluted to near
> extinction; you've highly diluted it to the point where it can be
> diluted no more.

Right, but I'd have the reverse situation instead, wouldn't I?  Since 
the tank is laying down, I need 600 ml of liquid to cover the films 
(side of tank up to middle of roll film spiral) -- regardless of 
whether I have one or five rolls in the tank.  So, let's say I'm using 
FG-7 at a 1:9 dilution.  With five films, that's 12 ml of developer per 
film (60 ml developer/5 films).  If I'm using a single film, I'm 
getting 60 ml of developer per film, although in both cases, I'll have 
a 1:9 solution of developer.

Which is more significant?  The dilution of the developer, or the 
relative amount of developer per film?

My point is this: let's say that I use 600 ml of 1:9 FG-7 and establish 
that my development time for normal contrast is 6.5 min with continuous 
agitation, using a single film in the tank.  If I then pop five films 
in the tank, 600 ml of 1:9 FG-7 and run it for 6.5 min, is it going to 
produce the same, or less, negative density?

I understand that I'm using less developer per film, compared to 
inversion agitation (when I'd have 1500 ml of solution, giving 150 ml 
of FG-7, or 30 ml per roll) and that this may be too little, but that's 
a separate issue.

The reason I ask this is that it may take two, three, or four runs to 
establish what that normal development time is -- since I don't have 
any guidelines for continuous agitation and I'm using a new developer 
that I haven't used before.  If I have to use five films per run, 
that's potentially twenty rolls of film just to establish my normal 
development time.

M.

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