dip&dunk tank

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What is a dip and dunk tank? Where can I get directions to build one? A number of folks have made reference to this beeing a good method for development. There is a large camera show in Houston near my home next weekend. If I purchase an enlarger or cold light head, are they all interchangeable? Do you use filters with cold light heads for VC paper, or do you need a special cold light head? Do you replace the condensor with the cold light head?

Thanks for the help............

-- tim kimbler (starman2@gte.net), March 11, 1998


Dip and dunk tanks are used for E6 slide processing, and are a little bit beyond something you'll be able to build yourself. Jobo builds them to order, which should tell you something about their complexity.

If you want to process E6 at home, get a tempering bath or one of Jobo's small manual processors. Matter of fact, even if you are processing black and white only, get a tempering bath or one of Jobo's manual processors.

As with any other head, cold light heads are made for specific enlargers. You can buy a collar adapter to fit a cold light made for a 4x5 Beseler onto a 4x5 Omega and vice versa, but that's about all the inter-brand interchangeability you get.

Filters and cold light heads work if you have new tubes in the head. Older cold light heads (such as the one I use) do not work well with VC paper, so you will need to stick with graded paper. If you want to use VC paper, the best choice is one of the new variable contrast cold light heads, but they are very expensive. And lastly, yes, you remove the condensor and drop the cold light in its place.

You should check out the following web sites for more information:

Black and White World http://www.photogs.com/bwworld/index.html

Darkroom Online http://www.sound.net/~lanoue/

Photo Source http://www.users.dircon.co.uk/~migol/photo/photosource.html

Jobo USA http://www.jobo-usa.com/jobofoto/index.html.

-- Darron Spohn (sspohn@concentric.net), March 11, 1998.

I'm afraid I have to disagree with the previous response - dip and dunk systems are not just for E-6. I have used them for C-41 and B&W as well as E-6. I don't think that they would be practical for a home darkroom, however. D&D systems are essentially large (a few gallons) vats that hold the processing chemicals. The number of vats depends on the process, one vat for each step. There is also a water jacket that surrounds all of the vats for temperature control. The film is loaded onto conventional stainless steel reels (for rolled films) or holders (for sheet films) and then a number of reels or holders are collected together onto a rack that holds a number of them. The rack is then lowered into the chemicals. The systems are designed so that the racks hang on the edges of the vats. Agitation is done by raising the rack out of the chemistry and putting it back in - I think this may be the origin of the dip and dunk name, but I don't know. There are some special considerations with these systems. The first is to keep accurate records of the film that you process and to replenish/replace chemistry according to manufacturer's instructions. The other is that there should be some sort of tight, floating lid system that can be placed on top of chemicals (especially the developer) to prevent oxidation/contamination from the atmosphere when the chemistry is not in use. It might be possible to cobble together some sort of D&D system for B&W processing since you wouldn't need the outside water bath for temp control. I've never heard of anyone who has done it though.

-- Tony Doucet (tdoucet@hydro.mb.ca), March 12, 1998.

Thanks to Tony for correcting my oversimplification. I have never used a dip and dunk tank, just read about them on Jobo's web site. They do sound too complex for a home darkroom. I have gotten excellent results using hand inversion tanks and a water bath for black-and-white and E6 processing, but prefer the Jobo so I don't have to slop chemicals while processing. The Jobos also require less chemistry than hand inversion tanks.

-- Darron Spohn (sspohn@concentric.net), March 13, 1998.

Manual "dip and dunk" systems are actually quite easy to put together. All you need is a series of Kodak 3 1/2 gallon hard rubber tanks and the stainless steel hangers for them. Each hanger can hold 1 8x10, 2 5x7s, or 4 4x5s. There are 13 hanger slots in each rack, so that means you can process 52 4x5s in each run. Great for conventional B&W work where film can be processed at ambient room temperature (but probably not good for T-max, since there isn't enough agitation during the dip and dunk cycle).

The drawback is cost of chemistry. Unless you do an obscene amount of processing, the chemicals will go out of date long before they are exhausted.

Another alternative is getting an old, used stainless steel sink or water bath that takes 1 gal tanks. The 1 gal tanks take only 4 racks per run, but the chemistry cost can be kept reasonable.

-- Gary Stuebben (stuebben@flash.net), May 26, 1998.

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