Mobile Darkroom and the Issue of Washing Prints

[Bill Burk]

Jim, I need a bit of clarification on the method you describe. The vertical trays are a fantastic idea and I've used this method with street-box camera designs for the chemistry (saves space and nothing really gets contaminated on the way down through the trays). In your method, when you say dump the tray vertically are you saying that you are dumping the water of the first tray into the next lowest tray?

Oh, I see what Jim was saying: Dump out the first tray's fairly contaminated water and since the tray is empty of water you can hold it vertically and peel the prints off one by one to lay into the cleaner water in the second tray.

The osmosis Ari was talking about is just what happens when a print sits in water, the fixer in the print spreads into the water naturally.

Are you going to be toning the prints too?

[Fragomeni]

I see. Thanks Bill! I anticipate I would be doing light selenium toning.

[Ari]

Ari, when you refer to osmosis are you talking about a system of some sort? Recirculation through an osmosis system? Clarify this thought for me please, thanks!

Francesco, I remember where I read about osmosis; turns it was about diffusion (high school was a while ago), and it's from Ken Lee's very informative website.
Here's the page: http://www.kenleegallery.com/html/tech/dishrack.php

It seems like the simplest and least expensive method.

[SpeedGraphicMan]

I remember reading an old army story about a staff photographer who had to develop a neg in the field and rush it to HQ.
He didn't have enough water to fully wash off the fixer. So all the guys in his group peed into the tray.

I don't know if this would be a recommended practice... But interesting to know.

The man was asked by HQ why the neg smelled funny.

[Fragomeni]

Haha, actually film can be developed in pee. There are some explanations of why on the web but it works.

I'm trying to get a little more info on diatomaceous earth but from what I'm finding it seems that it would actually work quite well. It is frequently used to filter water to drinkable condition and is approved for use by of number of international authoritative agencies. If it can produce clean drinking water then that water is surely clean enough to wash a print it I would think.