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Mixing chemicals-- distilled water?

Eric Domazlicky , Dec 13, 1997; 03:02 p.m.

I recently set up a small darkroom used right now just for developing prints. That's all I need since I just want to make contact prints and develop paper negatives from pinhole cameras. But when I mixed the chemicals for the first time I wondered if distilled water should have been used. I've looked around quite a bit and no one seems to address the question if the water used to mix chemicals should be distilled. Does it really matter that much? Or is that the reason none of my prints seem to have good blacks.


John Song , Dec 13, 1997; 07:55 p.m.

I guess distilled water will be better, but I've never used distilled water on my color, b&w or B/W printing chemicals. Just the water stright from the sink and it works just fine. I've never used pin-hole cameras before so I really can't tell you whether the black problem is the camera system itself or the developing, but I think you are over exposing the paper just a bit too much hence not getting dark blacks. Do you see the black(clear)on your negatives?

Andreas Carl , Dec 13, 1997; 09:55 p.m.

If you don't get good blacks, it's either exposure or development time, but has nothing to do with the quality of your water. I have used both distilled water and tap water for b/w, color and slide printing and found no difference. (Unless perhaps you live in an area with unusually "hard" water - but even that would not cause faint blacks).

Tim Brown , Dec 14, 1997; 09:33 a.m.

I generally use distilled water to mix film developer only. Since developer forms the image and film development is a do or die thing, distilled water seems like the consistent and safe way to go. Stop bath and fixer are more robust.

Halil K , Dec 14, 1997; 04:35 p.m.

The logic for the use of distilled water is consistency. The tap water qualities may change from day to day and definitely will change from location to location. Using tap water removes one of the variables from the equation. Having said that, I have used tap water for B&W when there was no distilled water available readily and did not see any ill effects.

Glen Johnson , Dec 14, 1997; 04:54 p.m.

I use reverse osmosis filtered water for all aspects of processing, including rinses. We have very hard water here, with a very high pH, and high total disolved solids. I don't know what effect this has on the chemical activity, but I do know that if I don't use distilled or ro filtered water for the final rinse, I end up with a white film on the negatives or prints, even when I use wetting agent.

I am even using ro filtered water for the water bath in the Jobo CPP-2. Before I started doing this, the processor would get covered with a white film. Now the equipment stays clean, and I've been very pleased with the results. I would definitely recommend distilled or ro filtered water if you have the kinds of problems with your local water supply that we have here in Dayton.

Tom Benedict , Dec 15, 1997; 02:02 p.m.

I use distilled water for these reasons:

First, I don't develop very often. The water around here isn't always the greatest stuff, so distilled water means nothing will be growing in my stop bath the next time I open the bottle.

Next, I don't trust the water to be the same from one day to the next. (Someone has already pointed out the consistency issue.) This means I can mix chemicals today, and they'll work just as well as the last time I mixed chemicals.

The water around here is pretty soft, so I don't suffer from the scum deposit problem someone else mentioned.

The two things I don't use distilled water for are rinsing (I'd have to own my own still), and for mixing Dektol. I mix the concentrate with distilled water, but I use the working solution one-shot, and haven't had any problems using tap water for that.

I agree with the other posts regarding your contrast problem. Bad shadow values can be because it's under-exposed, your chemicals are weak, the development time was too short, or simply that the paper you're using has really bad dry-down characteristics. The shadows on a wet print will always look better than the shadows on a dry print. But if it's REALLY bad, I'd look somewhere other than dry-down problems.

Best of luck,


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