Re: [Leica] Development question

[Mark Rabiner <mark@rabinergroup.com>]

Martin Howard wrote:
> 
> 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.
> 

How cool is it to have the tank laying down during agitation cycles it
would unnerve me and I've never heard of any one doing it? The Jobo
people i think go round and round and round and never stop. Seems like
your air bubbles would have a field day laying there still on the in
between times. An accident waiting to happen. Your negs would look like
the Adler Planetarium! Look the Dogstar! Woof!

Yes but 1:9 60 ml per rolls not near extinction I bet as FP4 is powerful
stuff. It could be a third that. It would not make a difference in a
tank of one or four just like the developers i mentioned last post.
Which is every commonly known developer except for FP4. But the bottom
line is you have to test to find out. And of course you want some leeway
as some crazy films (like Delta 3200 or T-Max 100) might ask for even more!
By the way i hope your not using the sulfite!

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

The dilution of the developer will only effect certain developing as to
rolls per tank or mls of stock developer per roll if the dilution is
near extinction and issues of how active the developer is from the get
go. Superadditive developer formulas will take a lick en and keep on
tickin.   Take a dilution and keep on totin.

But i would answer the former. The dilution of the developer. Because we
hardly ever run into the later problem; the amount of developer per roll
creating an issue where the amount of rolls in the tank must be consistent..
Not quite a chicken or egg formula

Rodinal can be commonly diluted 1:100 by slightly hard core
photographers and which is not on the documentation and we have no
variances in how filled the tank is with film.
That's the only commonly known example of a near extinction deeper other
than the way i used to mix up D23.. I cant see Rodinal going much past
1:125 but I bet on the internet there is some guy who does it 1:200 all
the time having lost some film speed he still swears by it. And where at
THAT dilution we'd have the capacity problem is anybodys guess. I'd
think there would be half a chance you would. But Rodinal is magic
developer and the smart approach is to never underestimate it.
Extinction could mean a list of things.
1. You are loosing film speednot to your liking.
2. You are getting mottling. Uneven development. Slides.
3. It's taking too long to develop the film and you're going crazy.
4. You've gotten a higher base plus fog level which does not appeal to
yo. Diachronic fog perhaps. Possibly print through-able. But i wouldn't
make a careeeer out if it!.
5. What was the middle part?


Mark Rabiner
Portland, Oregon USA
http://www.rabinergroup.com
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