As a latecomer to all this discussion, can I address the original OP? I also live in South Australia (known as the Driest State in the Driest Continent on Earth) and I've likewise struggled with my conscience as I contemplate building a darkroom in the next few months. The solution I've decided on, which may be of some use to you, perhaps, is to dedicate one of our rainwater tanks as my photography water supply. (I'll install appropriate filters). If it runs out in mid summer, that'll be a good time to go and shoot some more film until it rains again, or -GASP! - drag out the DSLR.
I have been using rainwater to do just that; my main objective for the original question, was how to best use any/all water I had access to regardless of it being mains, or rainwater from the tank.
The less I need to use, the better.
Last edited by ozphoto; 09-20-2011 at 03:13 AM. Click to view previous post history.
There were some studies done on film washing in the 1950s. A 2% solution of sodium sulfite was found to reduce residual thiosulfite in film to zero in two minutes. Film bathed this way, followed by a running waster wash of one minute has less residual chemistry in it than would a sheet of film washed in water alone for more than an hour. This is the mechanism used for the various hypo clearing agents.
Washing efficiency can also be improved by first bathing films in seawater or solutions of common table salt at that strength for ten minutes before a thirty minute wash with running water. One reference in the literature states that a ten minute bath with seawater dropped the residual thiosulfate content to 0.005 milligrams per square inch where after thirty minutes of tapwater washing alone only lowered it to 0.080 mg/square inch.
My preference is to use a hypo-clearing agent for about eight minutes, rinse the film thoroughly twice and then do a very low trickle wash for 15 minutes.
Since I have a motorbase, I started to use the Ilford method too.
After twice a 2 min. neutral-to-alcalic fixer, 2 min. KHCA and then 5 times 2 min. washing (20°C +/- 2°C) with continuous agitation (motor base) to finish with 2 min ADOSTAB.
According to the Kodak Residual Silver Test, which is actually a 1+9 KRST solution,http://www.google.be/url?sa=t&rct=j&...zc_Ny619mPuJEw, and a Sodium Permanganate 1/1000 test to test the washing, it looks good, but I am absolutely aware that those tests are not conclusive, and good for my peace of mind, but better these than notting!
I process in King's Pyro-HD, which is superb, thank you Sandy!
BTW, is it true that Pyrocat processed negatives are less archival?
Last edited by Philippe-Georges; 07-06-2012 at 01:00 AM. Click to view previous post history.
"...If you can not stand the rustle of the leafs, then do not go in to the woods..."
(freely translated quote by Guido Gezelle)
PS: English is only my third language, please do forgive me my sloppy grammar...
I go along with the "soak it out" policy. Preferable warm water but not hot enough to soften and damage the emulsion. I understand that if a bottle of even the most noxious liquid is emptied, refilled with water, left to sit, then emptied and refilled another 7 times, the result is clean water.
There's a test for residual hypo, but I don't know what it is.
There is a test for retained Silver Halides and a test for retained Hypo. Both should be used to establish whether your wash is up to the standards. Both are sold premixed by several chemical supply houses that specialize in photographic chemicals. I use the Photographers Formulary.
how does using lots of wash water harm the environment?
Clean water usually does not come for free. Water purification and transportation costs energy and most energy generation pollutes incl. nuclear power. Saving water is better for the environment in many ways. That's why low-flush toilets, low-flow shower heads, "grey" water circuits etc. are invented and encouraged.
I use the "Ilford method" and presume that Ilford tested that method before publishing it. I haven't done any testing myself.