I have the luxury of being on my own well and use ZoneVI film and print washers (probably no longer available) but if you are changing the water by dumping you could collect the "used" water and use it for some other purpose as long as the chemicals won't affect that use.
I'm in Adelaide too, and like you concerned and make an effort to save water.
I am just doing film at the moment, 135, 120 and 4x5 format. I develop in a rolling drum with motor...I like it because I can develop without shaking the damn tank, and I can roll for a long time at low temps around 13 degrees C. I used to hate the stress of exact number of inversions x exact time x exact temperature. That used to always get me uneven negs. Now I do it all with a cup of coffee watching the roller do the work.
So I wash in the roller too. First lot of water (300 ml) roll for about a minute, tip out. Next lot 5 mins (300ml) tip out, next lot again just 300ml roll for 5-10 mins, tip out. Take tank off roller and add demin water+photoflow, smooth of any bubbles. Let soak for couple mins. Lift out negs...usually couple rolls of 120, or 4 sheets of 4x5, and hang. I use a car wiper rubber to get the water off so they dry faster. I reuse the final water+photoflow a couple of times before discarding. I get perfect even negs which don't go brown with hypo stain.
Advantages...very little water used, and a final rinse in demin water (from the supermarket) avoids the problem of Adelaide's very salty town water.
Rollers and large diam plastic tanks can easily be made. I got an electric old roller from eBay for $50. It's really a dream not having to do the rattle n' roll by hand.
Washing is always a highly emotive subject!
Ilford reckoned 6 complete changes should be ok for Archival puposes, and I've always gone for 8 as a slight sop to still not quite believing that you can wash so fast. Film is obviously easier, and you can get away with 6-8 complete changes over 30second agitation periods, meaning that your film wash time is about 3-4 minutes!
Major riders: Temperature. Very cold water is never gonna shift anything anyway.
Big temp changes lead to reticulation, and may even loosen emulsions if truly excessive. There is little if any advantage to going beyond 21c.
Don't overwork your fixer. Older fixer can be almost impossible to remove due to silver complexes. Check the capacity and stick to it. Two bath fixing can boost economy significantly.
Hypo-clearing paper may be an even better idea if you want to go this route in FB.
ALWAYS ALWAYS ALWAYS carry out a silver test BEFOREHAND to check your methodology if you intend to work commercially, or sell prints. Selenium toning can show up fix problems also, silver estimation products are the most expensive option.
Michael Maunder has pointed out that seawater is quite a good substitute for HCA in the wash process, and has some historical context...
regular old cold tap water will work fine.
Originally Posted by Tref Hopkins
the way the "stuff" leaves the film and paper is
through osmosis --- water exchanges + soaks work.
it really doesn't need to be more technical than that ...
Accepted - cold tap water in a continuous flow/forced wash situation would be fine (assuming no thermal shock to emulsion; non-domestic tap water can get VERY cold in winter).
I'm unsure whether I'd agree that water temps were unimportant in a 'by changes' process though. I always make up a nice big jug of 21c water at the start, which does the pre-soak, mixes the dev and provides the plain water stop and the washes for me, so all my testing revolves around that. I believe I've read that colder water can slow the wash process a little, but I haven't tested my own cold winter tap water for film washing, so I can't really comment.
Others have pointed out that the 'by changes' approach can be pernickety and depend greatly on personal habits and local water quality for success.
I generally live by a mantra of 'bottle instructions will always work if followed perfectly, but may not be best results. If deviating from bottle instructions or mixing own chemistry be consistent and do your own testing to ensure it still works'.
Some swear by de-ionised final rinses: my filtered darkroom water gives perfectly clean negs with just a little photo-flo type rinse aid. Others may find debris on film if they do not use bottled water. Tap water is not a universal constant.
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Originally Posted by jnanian
Osmosis requires a membrane such as a cell in a human body.
Film contains no membranes, per se, and therefore only diffusion applies, not osmosis.
Originally Posted by Photo Engineer
i used the wrong word ...
i appreciate the correct lingo
Where does something like Ilford "Washaid" fit in all this. Or is it more of a paper wash aid.
Washaid is a hypo eliminator, not really needed with rapid fixers and film, probably not needed with rapid fixers and RC papers either, since the chemicals don't get the opportunity to get absorbed into the paper in the short fixing time. Fibre base paper, yeah, especially if using a traditional hypo fixer. If you have a huge jug of the stuff, then feel free to use it, if your thinking of adding it to your next shopping trip, then unless your using FB papers, I would skip it, get the Ilfotol wetting agent or a jug of Photoflo instead.
Originally Posted by SMBooth
See my Blog at http://clickandspin.blogspot.com
The greatest advance in photography in the last 100 years is not digital, it's odourless stop bath....
Your conclusions about when to use wash aids are right on, but I have a problem with the term "wash aid" being characterized as synonymous with "hypo eliminator". They are not at all the same.
Originally Posted by wogster
I know it sounds rather nitpicky, but I hope the terminology of wash aids and hypo eliminators becomes better understood and used since all these terms can be so confusing to beginners under even the best circumstances.
Wash aids like Kodak Hypo Clearing Agent are not hypo eliminators; the sulfite based wash aids are merely aids to wash hypo out of the paper.
Hypo eliminators are completely different; they destroy hypo within the paper rather than helping it be removed from the paper. Recent research suggests that hypo eliminators may actually be detrimental. It has not been fully studied, but total elimination of hypo may make for a less permanent print. Research suggest that an infinitessimal amount of hypo needs to be retained for best permanence. I do not know why. How much residual hypo? About what remains after a thorough washing using wash aids and plenty of clean water.
Wash aids are rather gentle in effect, merely allowing better diffusion of water and chemicals in and out of the paper base.
Hypo eliminators are rather different, much more aggressive chemically, and must be used with restraint, after the majority of hypo has been already removed through normal washing procedures(with the prior help of wash aids). I'm no chemist but if I get it right, a strong enough eliminator to destroy all the hypo would also seriously attack the image.
According to Ryuji Suzuki in http://wiki.silvergrain.org/wiki/Washing_aid :
"Hypo eliminator usually refers to a solution containing hydrogen peroxide or peroxide-releasing compound such as percarbonate, perborate or persulfate. These solutions may also contain ammonia, other alkaline agents, bromide, iodide, and other additives.
The idea behind hypo eliminator is to oxidize thiosulfate to harmless compounds that are not adsorbed by silver surface. However, it was later found that peroxide solutions damage and undermine image-forming metallic silver. Today, the use of hypo eliminators are discouraged."