randy_pitcher Posted March 5, 2003 Share Posted March 5, 2003 This has probably been asked before, but.... Can you use R/O (reverse osmisis) water instead of distilled water for mixing chemicals? I just got back into photography (other than p&s snapshots) after a 20+ year hiatus. I've taken a couple of classes, but didn't think to ask this question. -Randy Link to comment Share on other sites More sharing options...
crackers_. Posted March 5, 2003 Share Posted March 5, 2003 Is this like a 'water out of a Pitcher' joke? Link to comment Share on other sites More sharing options...
randy_pitcher Posted March 5, 2003 Author Share Posted March 5, 2003 Ha! Never thought of that!! That's my real name. When people ask me to spell it, I just tell them it's like a pitcher of beer!! Link to comment Share on other sites More sharing options...
chris_waller Posted March 5, 2003 Share Posted March 5, 2003 I have used something we call 'deionised' water which I would guess is the same thing and that seems to work fine. But if you need distilled water then there is a small electric still made, I believe, by Sanyo which can deliver about 4 litres an hour. I also use the water which results from thawing out the freezer compartment in my fridge. This is from ice formed from moisture in the air and is clean. Link to comment Share on other sites More sharing options...
crackers_. Posted March 5, 2003 Share Posted March 5, 2003 I think it's overdone - the water gets the blame for genuine technical faults. What can be the worst thing to happen? Organisms and minerals must be controlled/limited. The ph can't vary much if at all from neutral. I've had a lot of different supplies without visible effect. Probably the most critical point is the last liquid to leave the film, which should be sediment-free. Link to comment Share on other sites More sharing options...
lex_jenkins Posted March 5, 2003 Share Posted March 5, 2003 Yeh, what Bob said. Only reason I use distilled water is because our rural well water occasionally comes complete with actual chunks of limestone. Link to comment Share on other sites More sharing options...
gareth_harper Posted March 5, 2003 Share Posted March 5, 2003 If you get your hands on distilled water cheaply then use it. If not then just use the stuff that comes out the tap. It is worth getting hold of a certain amount to give film a couple of quick rinses after washing and before hanging to dry. It's also essential for toning, particulary when you consider the cost of toner, distilled water will not react with the toner and hence your dillutions will last longer.For general processing the tap stuff is fine. Link to comment Share on other sites More sharing options...
donald_miller1 Posted March 5, 2003 Share Posted March 5, 2003 The actual effects of RO water and distilled water are the same. RO water treatment removes both dissolved and undissolved solids by passing the water through a permeable membrane. Distillation accomplishes the same effect by converting the liquid to vapor and leaving the dissolved and undissolved solids behind as solids. Water softening works by ion exchange...the undissolved solids are exchanged for dissolved solids...basically the net effect is calcium, magnesium and iron are removed while sodium and chlorides are increased. I hope that this answers your original question. Link to comment Share on other sites More sharing options...
randy_pitcher Posted March 5, 2003 Author Share Posted March 5, 2003 Thanks everyone. I think I am going use RO treated water this evening. I am only doing film right now and saving printing for later. For now, I have to wait until another darkroom class is offered to print my negatives (or have them done by a lab). I am too cheap to rent a darkroom. Link to comment Share on other sites More sharing options...
al_kaplan1 Posted March 5, 2003 Share Posted March 5, 2003 Unless your water is unusually alkaline or acidic just filtering out particles is all you really need to do, and most tap water is pretty much free of particles. The ph is of most concern with film developer, because it has an effect on the developer's activity. I use filtered water for the wetting agent after the film is washed. A coffee filter works fine. Anything that gets through that won't be visible on any print under 20x24. Link to comment Share on other sites More sharing options...
john_cook1 Posted March 6, 2003 Share Posted March 6, 2003 I have used both distilled and R/O water in my commercial lab at various times for over thirty years. The results are the same for me. There are two advantages over tap water. First, minerals present in some water sources in large quantities (which will coat and contaminate equipment) have been removed. Second, you will get consistent development using a consistent water product. In my area, the pH of the tap water varies throughout the year. Road salt draining into the resevoir in winter, falling leaves in autumn and increased chlorine in hot weather all keep the local tap water changing. The choice between distilled and R/O water depends upon what is available in your area. I used to be able to buy a single 5-gallon cubitainer of R/O from a local chemical lab until they went out of business. I now must purchase distilled from another source which has a 25-gallon minimum. It's kind of like a lab timer. Consistency is much, much more important than accuracy. Regards, John Link to comment Share on other sites More sharing options...
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