Slot processor as a space saver

[Renato Tonelli]

In about two months I will need to print a good deal of 20x24 prints. The darkroom I am using is very small and I have had to get very creative when it comes to space but setting up and breaking down (a must since I am not the only user) is very time consuming, so...
Has anyone ever tried to build a slot-type "processor" like an archival print washer but with fewer slots and each isolated from the rest? I know about the Nova processors but the price would be prohibitive, especially with shipping from the UK.
I imagine such an animal for two fixing baths and another one for Permawash/Selenium. The first issue that comes to mind is agitation of the prints.
Have some coffee and discuss amongst yourselves... and please report back...:D

[Jon Shiu]

Some people just use a single tray and pour the different chemicals in/out.

Jon

[Rob_5419]

Your best bet might be to at Craigslist for any neglectful fish owner.

The fish tanks make brillant set up tanks, with the bonus of a fluid filtration system and temperature control.

[ericantonio]

Your best bet might be to at Craigslist for any neglectful fish owner.

The fish tanks make brillant set up tanks, with the bonus of a fluid filtration system and temperature control.

Somewhere on the innernet, I saw someone make it from fishtank. How the guy moved it around, I don't know. I don't know how he drained it either. And what would you use as a paper holder? Too bad there isn't a US dealer anymore. Perhaps some folks on apug can get together and create an LLC and....wait a second, that sounds like a good idea!

I like the 1 tray solution for large prints. Seems easier and cheaper. I use that method for alt-printing.

[Rob_5419]

Somewhere on the innernet, I saw someone make it from fishtank. How the guy moved it around, I don't know.

Either telekinesis or biceps power.



I don't know how he drained it either


The ladle scoop method (laborious) or suction pump approach (a little more expensive)


And what would you use as a paper holder?

You've not tried it this way then? ;)

Coat hanger wire, outstretched - with weights on either end of the fishtank. Nova slot clips can hang from these.


Too bad there isn't a US dealer anymore.

For fishtanks?? :eek:

[David A. Goldfarb]

Another option is a print drum. I've got one for 20x24", so they're out there.

[Bobf]

If you DIY it then the Nova slot clips could do the job of holding the print. One will hold a 12x16 fibre print easily (the largest Nova slot thingy I have - though two are sometimes needed for stability when lifting a floppy fibre print out of the slot) so two would probably hold a wet 20x24 - but a rigid holder for three in a row would probably be safer... For agitation, I just move the print up/down every 4-5 seconds. The Nova slots have a waffle pattern to stop the print sticking - no idea how necessary that is.

Worth trying the single-tray idea I suspect. One tray and three large jugs = a lot cheaper too!

Good luck, Bob.

[Mattg]

I've been very happy with my Nova 12x16" Monochrome 3 slot model.

Before I bought it I thought it seemed expensive for something I could make myself. Well the thing is I couldn't have made anything nearly this effective myself. The thought that has gone into the design and manufacture of these units makes them worth the price. Maybe a used unit can be found?

I have tested the effectiveness of agitating the print with the Nova print clip and have found it produces much more even development than tray processing if both methods are used continuously but gently.

There are some disadvantages to using a vertical processor; you can't rub the print or use warm water to effect local development control, they probably aren't appropriate for toning baths, they are best used kept full and replenished rather than emptied and refilled often and (importantly for you) the larger the paper size the more difficult it becomes to handle when vertical. I'd be very interested to know if anyone has used one to process 20x24" paper.

I need two sessions when using a slot processor:
1. Development, stop, fix, wash.
2. 2nd fix, tone, wash.
The second session uses trays instead of the slot processor.


Good luck,
Matt.

[Ed Richards]

Google "Dev-Tec 200A"

A 20x24 drum processor for $100, add a motor for another $60.

[Cliff McMann]

Years ago I worked in a commercial lab that used to print murals. They had "trays" made from 1/2 of an 8" or 10" PVC pipe. There were caps on both ends and a smaller 1/2" pipe set below the level of the edge of the large pipe, running lengthwise. To process these large pieces of paper you would fill the tray to the level of the smaller pipe then roll the print up and stick one edge of the print into the tray under the smaller pipe (this kept the print under the chemical). Take hold of the edge as it came out of the chemical and roll it up on the other side. You would continue to slide/roll/unroll the paper back and forth through the chemical for the alloted time. With those large prints 24" x up to 8 feet 2 of us would work with each piece of the mural. I'm not sure this would be easy with one person but you may be able to adapt the idea of a narrow tray to work. We were printing on RC papers which do seem to be more flexible than most FB papers, so that may or may not affect you.

[Jim Jones]

Narrow trays for processing as Cliff described may be available at garden or wallpaper stores.

[al olson]

My darkroom is very cramped so several years ago I purchased a rack from B&H that allowed the trays to be staggered in a vertical stack. Mine was for 11x14. I don't remember if they had them as large as for 20x24 trays or if they even carry them anymore, but, if so, it may be a solution.

A couple of years ago I bought the Nova 12x16 which is much handier. The small surface area keeps the chemicals fresher over time and I always replenish before I start a developing session. My process is similar to mattg's for 2nd fix, washing, etc. The nice thing about the vertical slot tank is that I can step into the darkroom to make a couple of prints and everything is ready to go.

For anything larger up to 20x24 I use the Jobo tubes in my CPP-2. This, however, is not an efficient answer for processing large quantities of 20x24s. If you can build the 20x24 slot processor, I would go for it. It is easy to use and the print quality (even if the chemicals have not been used for a couple of weeks) is excellent.

It should be borne in mind, however, that the pressure head for a vertical processor may be critical. Nova's instructions for filling the slots in the 12x16 are that no slot has 500 ml more than any of the others. Each of the slots takes about 1800 ml so doing a complete refill is a real pain ...

[Scott Davis]

I built one out of Plexiglass in 11x14. It worked well enough, but it convinced me to get a Nova 16x20 processor for the advantages it offered (temperature control, ease of use for draining and cleaning). If you can drill in some drains, I think a home-built 20x24 slot processor would be workable, so long as you arrange it with the 24" dimension on the horizontal, not the vertical. For the base plate, you'll want at least 1/2" plexi, maybe 3/4". The side walls and partitions should be at least 1/4". It will be quite heavy, but manageable.

[jeroldharter]

I think a homemade 20x24 would be difficult. Even with narrow slots, the required volumes would create substantial pressure on the outer walls of the tanks. You would have to provide some bracing/re-enforcement. Also, it would be quite tall, so if you set it on top of your sink and then try to dunk a 20 inch tall piece of paper in without kinking it you would at least need a stool. Also, the weight would be substantial and you could not lift it when full. You would need to provide drainage in the design.

I think a better solution is to do what I do - single tray processing. I use a single 20 x 24 tray. that requires about 4000 ml of each solution which I put in 4000 ml plastic beakers purchased from US Plastics. They are rigid, have handles, and pour well.

I pour in the developer, then pour out the developer into its beaker. Lifting the tray properly without spilling takes a little practice but I never spill anything now. Then I do the same with stop bath. Then I rinse the print and tray with water (a hose type connection at the sink is very helpful). Then 2 rounds of fixer. Then a rinse, then PermaWash, then either rinse before the washer or selenium toning.

Sounds like some fussing but you get into a good rhythm. Minimal smell from open trays. Less oxidation of the developer. Less transfer of one solution to the next because of the rinsing. No stains in trays even from developer and selenium. When you pour the chemicals back into the beaker, you pour gradually at first and the wet print sticks to the bottom of the tray and will not fall out. When you rinse, be sure to rinse under the print also.

Also, I do a lot of batch processing. For 20 x 24, the most I will do at one time is 3-4, but for smaller sizes as many as 8-10. I develop to completion so the development times are less critical. I slide each sheet into the developer quickly, turn on the timer, and then I continuously interleave the prints in the tray just like developing negatives. the larger prints require more attention to handling so they don't bend. I use latex or nitrile gloves (with a separate beaker of clean water for rinsing my hands between steps). Even a stack of 10 11x14 prints is unlikely to fall out of the tray when pouring out the chemicals if done properly.

It took me a while to convince myself of doing it this way, but I would never go back. The process is much cleaner with less contamination, minimal print handling, no tongs, minimal vapors. Also, it is easy to use more than one developer during a print session. Just have a different beaker with developer #2 on hand. I use only liquid stock solutions which are easy to mix in the same beakers I use for processing. I use one-session chemicals and dispose of them when finished so there is minimal storage.

[Peter De Smidt]

I'm making a 20x24 inch slot processor out of 1/4" abs. All of the pieces are ripped. Now I have to cut to length and assemble. I'm thinking about putting a Won Titanium fish tank heater in the bottom of the developer slot. I will build a plywood box to hold the tanks, using styrofoam to insulate the tanks and provide some rigidity. The box will be on castors and low to the flour. (I have a floor drain). With floating lids and the right chemicals, the solutions ought to last quite a while. I'm planning on using a plastic tray, ala the Nova FB processor, to do fiber paper.