Mobile Darkroom and the Issue of Washing Prints (Cross-over thread from LF Forum)

Hi all,

I initially posed this over at the Large Format Forum but figured that this is a perfect for a topic here on APUG as well.

I've been doing considerable traveling lately, including a cross-country trip that brought me from Arizona to Pennsylvania. I've towed a small travel trailer behind my Land Rover which has made for perfect campsite hotel room. I'm now considering converting the trailer into a functioning mobile darkroom. I have no reservations about the idea except that the trailer does not have a hook up for running water. This relates to the issue of washing prints. Now, I've started to do quite a bit of research on people's methods for washing prints without running water, something that is actually not that uncommon apparently. I'd love to hear opinions on how to approach the issue. The only issue that I've come up with regarding this mobile darkroom idea is the concern of running water so I'd love to work out a solution for this.

There is always handwashing prints in trays using the rince-and-dump method but that is tedious and involves carrying a large amount of water. I have a reservoir tank of a few gallons but I don't think it would work well. I've heard of people using recirculating methods of various sorts. These systems use very small amounts of water and recirculate the water washing the prints. (FYI, for those shaking their heads at the recirculating concept, some recirculating washers have been shown to be among the most efficient in terms of cleaning prints thouroughly. Google for more information if curious.)

There's also the concept of using a variation of the rince-and-dump method using filtering of some sort to efficiently clean and reuse the water. I know people use diatomaceous earth (for pool systems) to filter Chinese Amidol. Diatomaceous earth is inert and capable of filtering down to the Chlorine molecule so very efficient. I wonder if this could be used to filter water for washing prints. It might look something like this: using two trays of distilled or otherwise clean water for washing prints, wash the first print in the first tray for five minutes then transfer the print to the second tray of water. While the print is in the second tray of water, pour the first tray water through a funnel containing diatomaceous earth and lined with a filter (coffee filter would work) into a jug. Once the water has filtered, pour back into the first tray to which the print can now be returned and the filtering process can be repeated using the water in the second tray. The process would repeat for however long was necessary to wash the prints. Thoughts?

Any insight into this will be hugely appreciated! Thanks!

P.S. Sorry if there is any odd formatting in this message. Internet is shotty where I am and I'm writing this on my iPhone.

Here is the link to the thread on the Large Format Forum for anyone interested in that side of the convo.

When would you have access to a regular sink again? If the prints were fiber, could you leave them in water until being able to wash them later or do you need to be fully sustainable in this trailer. Or could you let the prints dry and wash them fully later?

Diatomaceous earth could get a bit messy if you're travelling around and there's the question of how to dispose of it once it's reached saturation. There are many types of commercial water filters that might be easier to use. Camping stores have portable ones or you might be able to rig up something more permanent using a household filter with replaceable cartridge.
Wonderful project. I envy you. Good luck.
Les

Off-topic... but i just had a look at your website Francesco, and your images are wonderful! Good luck with sorting out your mobile washing system. I am very interested also.

David Vestal once wrote an article suggesting that leaving prints in a tray/basin overnight was as effective as any archival washer. I'm pretty sure this was PhotoTechniques magazine.

Francesco,

It's really a question of volume, as I see it. I imagine you could make two to five prints or so and use tray soaking and 5 or 6 changes of water and wash quite effectively with very little water - 10-15 liters would do the trick. You could install a water tank and a holding tank that would easily have that capacity or more. The process would be rather labor-intensive, but would work fine.

The problem would be when your printing output was larger. Then the storage of water, both fresh and waste, would present a problem.

I made some plans for a trailer darkroom once, which never got built. However, I made provision for water in and water out. My thinking was this: Fresh water from a regular water line is easy via a hose. No problem there. Getting rid of waste water from washing and chemicals was the big concern. The best solution is, of course, to have provision to hook up to a municipal sewer system. Many RV parks, etc. have "full hookups" which include sewer, water, and electricity. Being able to pull your "darkroom" into one of those for a day or two and being able to use water, power and sewer may be well worth the fee.

A "hybrid" solution would be to have water in, and a rather generous holding tank, which you could then empty at trailer dumps. You could likely dump chemicals that way as well, as long as you didn't use anything exotic. Since water and photo chemicals are not so nasty, you could even empty your holding tank manually, carrying buckets of waste water to any municipal sewer "inlet" (read public toilet or sink drain). That would at least eliminate the need for lots of fresh water storage.

Ways to reduce water usage when washing would help as well. An archival washer with thin slots doesn't take that much water. You don't have to have constant water throughput. You could use a washer "fill-and-dump" quite easily. Five changes over an hour, spaced, say 5 minutes, 10 minutes, 10 minutes, 15 minutes, and 20 minutes would likely give you a real archival wash (of course you would test for residual hypo and adjust to get the wash you need).

I'm imagining a batch of 12 11x14-inch prints... Holding tray with water would be 2-3 liters. Then there's the hypo-clear: 2 liters and finally the wash. Let's say the washer holds 11 gallons (rather a large estimate, based on the Versalab 11x14 washer specs.). That's roughly 40 liters times five changes equals 200 liters. Add the chemicals and holding tray comes to 210-220 liters, plus a little cleaning up water = approx 250 liters. All that would fit in a 70-gallon tank or equivalent.

You may be able to get by much better than that. Sumitek Cascade washers advertise an archival wash of 16 11x14 prints with a flow of just 4 gallons (15 liters). That plus the washer capacity of 35 liters makes only 50 liters of wash water for a batch. That plus chems, etc. would easily fit in a standard 40-gallon tank. (see http://www.summitek.com/cascade.html )

Hope my brainstorming helps a bit,

Best,

Doremus


www.DoremusScudder.com