5x7 Daylight Film Developing Tank Design Ideas

Discussion in 'Darkroom Equipment' started by rshepard, Feb 13, 2011.

  1. rshepard

    rshepard Member

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    I do minimal agitation development with pyro on my sheet film and have a Yankee tank for the 4x5 that works very well. There are apparently no equivalents for 5x7 film so I will build my own from plastic. I've thought of several ideas on how to do this (without the need for gallons of developer and fixer) and have not yet settled on a design that will let me fill and drain liquid in a light-tight system. I know that Jobo print tanks can be adapted to the job, but they need to be rotated and are not suited to stand development unless the tank is completely filled.

    I'm asking here for either plans of a practical working system or ideas on how to ensure no light enters the tank yet I can turn it over to pour out developer, stop bath (water), and fixer. I bought some 5x7 negative holders on eBay (now I need to find where I put them), or I can route slots in plastic to hold the film.

    Please share your thoughts with me.

    Rich
     
  2. ChuckP

    ChuckP Subscriber

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  3. ChuckP

    ChuckP Subscriber

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  4. werra

    werra Subscriber

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    3-reel Paterson and taco style?
    I'm in the process of finding out reasonable way to do 5x7 stand myself. Other ideas involve hacking jobo 4x5 reel but supporting the film only from the short sides does not look too promising.
     
  5. holmburgers

    holmburgers Member

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  6. paul_c5x4

    paul_c5x4 Subscriber

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    About the best bet for sheet film up to 10x8 is the Paterson Orbital - You can get away with 500ml of chemicals for stand development and as little as 100ml for constant agitation. In practice, I prefer to use 2-300ml for the later and anything up to 1l for stand.

    I have heard of people using an open tray & slosher inside a light tight wooden box, but that method requires total darkness to move from dev to stop/fix. The other alternative is a BTZS tube setup, but to be honest, I don't know how much solution you'd need for stand development.
     
  7. rshepard

    rshepard Member

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    Thanks, everyone! The Morse system on eBay seems to be for 4x5 as those are the hangers that come with it.

    I'll keep working on the idea and when I get something I like I'll post the results here, with images.

    Rich
     
  8. graywolf

    graywolf Member

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    Why should you need to turn it over, just put a dump valve in the bottom of the tank. Fancy motors, and expensive electronics is what people think of today. In the old day a bulk film processor, usually 3.5 gallon, used nitrogen burst agitation, and dump valves. Some of them had a robot to move the hanger rack from tank to tank untouched by human hands, but most of them were just a case of the the darkroom guy walking into the film room, switching off the lights, lifting the covers, and moving the rack from tank to tank, replace the covers, turn the lights back on and go do something else until the timer buzzed again. Of course you could make a smaller unit if you did not need to process 35 roll of film at a time.
     
  9. rshepard

    rshepard Member

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    graywolf,

    I've thought of an outlet on the bottom to drain the fluids. I use the developer only once so mixing up several gallons for a few sheets of film is not practical. As I wrote in the original posting, I use extreme minimal agitation with my sheet film. If I wanted to agitate it I'd put the large sheets in a Jobo print drum and spin them on the processor.

    Thanks for your thoughts,

    Rich
     
  10. mgb74

    mgb74 Subscriber

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    Do you consider homemade BTZS type tubes (sized for 5x7) to use too much developer (http://www.apug.org/forums/forum43/47756-btzs-tubes-diy-homemade-build-your-own.html)? Without measuring exactly, I suspect a 2" pipe would be adequate. To reduce interior volume, you could insert a solid or capped tube in the center attached to the bottom plug so it remains centered. Of course you are limited to 1 sheet per tube (unless you increase the size of the tube to hold multiple sheets).
     
  11. cj8281

    cj8281 Member

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    I built one for doing 4x5 and now I am going to build one for doing 5x7 for paper for my pinhole camera for WWPD. Pictures here:http://photo.net/black-and-white-photo-film-processing-forum/00XrEp It is just for doing Black and White, I know others have built ones for doing color.
    You could upsize this and do 5x7. http://www.btinternet.com/~g.a.patterson/photos/lfdevelop.html. I built one for doing single 4x5 and it only uses 6 ounces of solution. It did not cost as much as my rotary processor but the rotary will do 2 sheets at a time.