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View Full Version : "Wiping" (aka Stupid Tray Processing question)



healyzh
24-Dec-2018, 14:37
I've been fighting with some intermittent processing issues using a Jobo 2840 drum for 8x10 and 11x14 film. I now know those issues are due to the tank clips to hold the film in place, and the agitation done by a Uniroller or a Simma Roller. As a result I'm in the process of moving to processing in trays in the darkroom.

As a refresher, I pulled out my copy of Ansel Adams "The Negative", and "The Ansel Adams Guide - Basic Techniques of Photography - Book 1". Both mention placing the each sheet on the top of the stack with a downward "wiping" action.

What I'm missing is, what is a downward "wiping" action???

Zane

Two23
24-Dec-2018, 15:02
Don't know for sure but if it were me doing tray develop for 11x14 I would do them one at a time. I'm afraid of scratching emulsion.


Kent in SD

Jac@stafford.net
24-Dec-2018, 15:11
My two cents: You would do best to work out the constant agitation of the drum. Tray processing involves far more human errors. So, let us step back and find what is really going on with your roller processing. Step by step. What's with the 'clips', and what is wrong with the negatives? First things first. (I find rotary agitation in a tank to be the very best.)

healyzh
24-Dec-2018, 15:30
Don't know for sure but if it were me doing tray develop for 11x14 I would do them one at a time. I'm afraid of scratching emulsion.


Kent in SD

I'm definitely inclined to agree with regards to 11x14. Besides, with my setup I can only handle a single sheet of 11x14 at a time, it doesn't matter if I'm doing drum or tray.

I'm looking at being able to do more than one sheet of 8x10 at a time with either Tray or "Dip & Dunk", and the tray requires less chemistry, which in turn means less cost. I've done multiple sheets before, but I'm trying to ensure that if I do this, I do it in the best way possible.

Zane

Peter Mounier
24-Dec-2018, 17:01
I don't disagree with the comments above. But to answer your question about the downward motion, I think they're saying to hold the film at about 45 degrees to the tray and lower it down into the developer while at the same time sliding it into the tray. That way there shouldn't be any air bubbles, as there might be if you were to just plop it on top of the developer and push it down into the tray.

healyzh
24-Dec-2018, 17:20
My two cents: You would do best to work out the constant agitation of the drum. Tray processing involves far more human errors. So, let us step back and find what is really going on with your roller processing. Step by step. What's with the 'clips', and what is wrong with the negatives? First things first. (I find rotary agitation in a tank to be the very best.)

The primary issue appears to be too much agitation. I'm getting uneven development, the most obvious was the problems caused by the Jobo clips for the 2840 drum. Then there is uneven density at the edges, as well as blotches and streaking. The strange thing is a busy image turns out perfect. One with large amounts of even tones shows the issue. The severity really shows up once I took some photo's for testing of my garage door and siding.

I can provide more details later, but it's Christmas Eve, and I'm supposed be somewhere. :)

Zane

healyzh
24-Dec-2018, 17:22
I don't disagree with the comments above. But to answer your question about the downward motion, I think they're saying to hold the film at about 45 degrees to the tray and lower it down into the developer while at the same time sliding it into the tray. That way there shouldn't be any air bubbles, as there might be if you were to just plop it on top of the developer and push it down into the tray.

That would make sense. I'd incorrectly assumed that this would be easy to google, but my google-fu has failed me, and I can't find anything by anyone else confused. :)

Zane

Tracy Storer
24-Dec-2018, 18:59
Not sure what Saint Ansel meant by "wiping", but I pretty much place the film flat on top of the stack and gently press down before sliding the next sheet out from the bottom. I have tray-processed the vast majority of my sheet film for 30+ years and get even development and very very rarely scratch anything.

Drew Wiley
24-Dec-2018, 20:17
I develop sheets emulsion up in dimple-bottomed oversized stainless trays. I won't go into detail, but "wiping" certainly isn't an idea I'd want to convey. In each respective tray, the sequential sheets are carefully laid down atop one another. Then they are carefully shuffled at regular intervals by carefully lifting up the balance of the stack, pulling out the bottom sheet, then carefully placing it on the top of the stack. What I never want is the corner or edge of a sheet interacting contacting the emulsion of another sheet and potentially scratching it. As far as even agitation goes: 1) sufficient solution, 2) never too many sheets - you should be able to gently shuffle them within the alloted rotation time, 3) oversized tray, 4) after each shuffle, I rotate the whole stack 90 deg (which an oversize tray allows), so that all four direction get the same amount of development. I'm sure there's a point at which sheet size would get a bit intimidating in a tray, but 11X14 doesn't sound very spook. With DRUMS, 1) you have to be quite carefully that nothing like a clip or projecting divider causes a flow disruption (I've had to modify certain drums in this respect, 2) the fill and drain must occur rather quickly in relation to development time (Jobo drums are rather slow due to the small drum opening), 3) you need to introduce a 3-way rocking motion, especially if solution volume is modest (a single eccentric rather than round roller on a drive rod will do this, but that might not work on a Jobo because it is cog driven from the front), 4) speed must be optimized to the process, and in this respect, I think Jobo at even the lowest setting is generally too fast, risking excessive frothing and oxidation of some developers. But a drum can simply be rolled back and forth in a sink bed. The trick to proper temperature is not just a water bath or even reasonable ambient air temperature, but maintaining the dev temp inside the drum. This is accomplished both via sufficient volume and by insulating the drum. I'm not bashing Jobo; I use their hand inversion tanks for roll film. But their ABS plastic walls are quite thin, and for sheet processing I'd wrap some kind of "wet suit" of insulating rubber around them, if I did use them. I happen to use noryl drums for fussy work - a much better insulating but comparatively expensive thermoplastic.

Jim Jones
24-Dec-2018, 20:18
My system is much like Tracy's. I develop only a few negatives at a time. After a pre-wash and while the negatives are draining, I peel off the top one, place it E side up in the developer, push it down, and slosh the tray once. This is repeated until all negatives are in the developer. Then I lift the edge of the stack, peel off the bottom one, and push it down on the top of the stack. The tray is sloshed each time. When it's time for the stop bath I peel from the bottom of the stack as before, drop the sheet into the stop bath, and slosh the tray once to insure the emulsion has complete contact with the stop bath. I don't touch the stack in the stop bath until all sheets are out of the developer. The process is the same for subsequent stages. This does require some care to prevent splattering of the chemicals or transferring chemicals on the hands into previous trays. The same process works well for prints, too. even when processing many at a time. I still have many hundred 8x10 RC prints from 1973-1975 processed this way for press releases where longevity was less important than prompt delivery, and very few show problems from chemical contamination.

Late note: Drew explains this method much better.