[pure-silver] Re: re-using DDX


----- Original Message ----- From: "Ryuji Suzuki" <rs@xxxxxxxxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Friday, March 31, 2006 3:20 PM
Subject: [pure-silver] Re: re-using DDX


From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
Subject: [pure-silver] Re: re-using DDX
Date: Fri, 31 Mar 2006 15:05:15 -0800

Ideally, the method of replenishment should maintain
developer properties constant. This is determined for large
scale machine processing by frequent sensitometric testing
and by chemical analysis. It is this kind of control I meant
by being too bothersom for small volume home darkrooms. Now,
some people do a lot of color work in semi-automatic
machines, like the Jobo, probaby testing like this becomes
reasonable and desirable at that point.

For b&w film processing, if you use bleed system, you can omit
sensitometric tests until a reasonably large number of rolls per
liter. At that point, you can simply restart the replenishing system
with fresh developer. You are still sparing a lot of chemical waste,
which may be significant in some areas.

Top up system is a lot more PITA. Top up method is not good enough for
industrial use by today's standard, and it's too PITA for small scale
darkroom.

For quality oriented users, bleed system is the way to go.


  OK, I believe you :-)

---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx 

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