Archived posting to the Leica Users Group, 2005/04/21

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Subject: Was [Leica] End of an Era - Now photographic chemicals
From: TTAbrahams at (
Date: Thu Apr 21 19:17:18 2005

 Most of the photographic chemicals in use today are rather benign. The 
developers are diluted heavily and pose no environmental threat. Developers 
Xtol and PCK are Ascorbic Acid-based and probably improve the waste! D76 and 
derivatives of that formula contain chemicals that are used in food 
processing (Sodium Carbonate) and  pool cleaning solutions (Sodium Sulphite) 
and  are 
not dangerous for septic systems and treatment plants.
 The biggest culprit is  the used fixer. The silver dissolved in fixer can 
cause problems in septic systems and in large quantities also affect 
plants. Mind you, it takes 80 rolls of 35mm film to get an ounce of silver 
your fix so the volumes usually encountered in a private darkroom are not 
serious. Silver recovery is possible but it is really not feasible unless 
you are 
doing commercial volumes. I used to do it by keeping a sealed bucket
(with a small vent pipe) with pure steel wool in it. You poured the fixer in 
the bucket ensuring that the steel wool was always covered by fix. The steel 
wool attracted the silver molecules and slowly "cleaned" the fix. It is a 
smelly process so you have to keep the bucket outside and in the end you 
have a 
black goo in the bottom that you could bring to a recovery plant. With 
silver price hovering around $5-6/ounce it is not worth it unless you do a 
couple of 100 rolls of film/month and lots of fiber based prints.
 There are a couple of developers that are quite "clean". The PCK 
(, a Patrick Gainer formulation that works very well with 
Tri-X, Acros, 
etc.  - its main components are Vitamin C (Ascorbic Acid), Phenodine (0,3 
grams for 30 rolls), Borax (a naturally occurring alkaline - 20 Mule Team 
from Death Valley) and Sodium Hydroxide (sounds ominous but is a Kodak name 
Red Devil Lye). The PCK is diluted 8 times for use so it is virtually 
exhausted after use.
The classic Rodinal contains some not so healthy components but with 
dilutions ranging from 1:25 to 1:125 in normal use it is again so diluted 
that it 
poses no threat.
 Some of the Pyro formulas are dangerous in concentrated form but once they 
are in suspension with water the dilutions are so great that they are 
virtually harmless.
 If you are a heavy fixer user (5-10 gallons a month) you should probably do 
the right thing and take  the used fix to a collecting place rather than 
jeopardising your septic tank system. 
 City systems get more "crap" into them than even the most eager darkroom 
users could amass;  oil-drips, leaky radiators, detergents from households, 
roadsalt after the winter, etc.
Keep printing and processing,
Tom A
Tom Abrahamsson
Vancouver, BC

Replies: Reply from s.dimitrov at (Slobodan Dimitrov) (Was [Leica] End of an Era - Now photographic chemicals)