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Discussion in 'B&W: Film, Paper, Chemistry' started by DAK, Feb 7, 2008.
What aspects of water quality are important for processing film?
I live in a hard water area and have found no problem using tap water for almost everything - the only difficulty has been with lime scale precipitate with certain toning processes and with the final rinse water for films. In these cases, I use demineralized water (which has run through a BRITA filter jug with an activated carbon filter). Other swear by distilled or deionized water, but I have never felt the need for these, which are expensive in large quantities.
I have found that I can get by with filtered water in my area, as in I just filter it with one of those Bri**a water jugs with the charcoal element.
Water quality is a local thing. At the least, I would consider filtering, as I do. Some folks find that their local water works ok for washing, but use distilled for mixing chems. Since that is low volume, they arent too bad off.
It pretty much boils down to what you can get away with. Best way to really know, is to try it. The most common complaints seem to be sediment, and hardness.
Not sure what the water quality is like in Tucson, but if its anything like Phoenix, I would suggest you make up your processing solutions and wash water using reverse osmosis water.
Reverse osmosis water from the supermarkets is pretty cheap and good enough for most processes.
Ilford have an inversion wash method on their film product sheets which is reasonably economical with the amount water used - although some on APUG forums think the number of water changes are at the bare minimum and if your worried about archival permanence of your film you should do it a few more times.
I use a de-ionised water without wetting agent for my final wash with sheet film to avoid those annoying drying marks.
Reverse osmosis water, wetting agent and a squeegee should be fine for roll film
The municipal water supply in my town is known to be hard and I never had a problem with the photo chemistry. I can remember reading something negative about water softening filters - AA was the source in one of his books.
Reverse-osmosis filtration (also known as ultra-filtration) involves the separation of molecules - very slow, a few drops/minute w/o extreme pressure - producing a very pure grade of water. I would guess this would be more expensive and if my water needed this kind of treatment I would consider relocating. Buying water from the super market seems kind of crazy too me, especially for archival washing prints (30-60 gallons/hour).
Thanks for the responses. I have been using filtered water without any problem that I can recognize. But every time I mention a little problem (such as magenta color of 120 Tri-X negatives), a mentor says it's the water. One way to find out is to get some reverse osmosis water and run a test. Our water department publishes monthly data on water quality by region of the city. My unasked questions were: how hard is too hard, and how much total dissolved solids(TDS) is too much for photographic purposes? I can get numbers for both of these variables. Dave
the magenta color is a sign you need to fix a little longer and wash a little longer.
How long are you fixing?
The old rule of thumb was that if it is drinkable it's useable for darkroom chemistry, especially for fixer.
You would be amazed at what your tap water can do if you boil it rapidly for five minutes in a glass or stainless steel container, then run it through a simple filter. Some old lab rats used a funnel with a ball of cotton in it. I use coffee filters, mesself.
But, then again, I rarely use tap water, because I am set up to collect my AC runoff water in the long, hot, humid, DC summer and store it in large plastic carboys. I filter it before I use it though and it works fine even for wetting agent.
John, Mount Vernon, VA USA
I avoid the above mentioned issue by using distilled
water in a least water manor. All chemistry is prepared
and dilutions made using distilled water. The Ilford
5-10-20 sequence is used in a leisurely way
Only very dilute fresh fixer as a one-shot is employed.
Film goes directly from developer to fixer. The fixer
loads only very little with complexed silver so will
wash cleaner with the little water used.
Total water used, developer, fixer, three washes,
and a PhotoFlo, three liters. All solution volumes
five hundred milliliters; one 120 roll film. In my
neck of the woods, sixty cents/roll. Dan
I use filtered water. Solution volumes are 600 ml. I presoak for 2 minutes. XTOL 1 +1. A water stop bath. Fixer is TF-4 at 1 + 3 for five minutes, one shot. Wash is a modified Ilford of 5,7,10,15,20 sequence, wiping out tank between fills. Did a 35mm roll of Tri-X yesterday, fixed for 8 minutes, no magenta. But I think there may be a difference in the film base between 35mm and 120 Tri-X. A previous roll of 120 Tri-X produced a very nice grape Kool Aid after the presoak, the 35mm didn't. Dave