processing 8x10 (B&W) with unicolor motor base and tube

[lenser]

Okay, I've done a bit of hanger processing of 8x10 sheets, but that's quite wasteful with 3.5 gallon tanks and only a handful of sheets at a time.

I bought out a bunch of darkroom stuff at an auction this weekend which included a nice Unicolor power roller base and processing drum. Got me to thinking, can this be used for processing for a single 8x10 sheet at a time and using only a few ounces of chemistry per sheet.?

Seems like it would be about the same as using my Kindermann roller processor with 35mm and 120 reels and tanks, but would this unicolor gear give smooth and even processing, or; since the agitation would be continuous and in a non-varying track, would it cause silver trails like letting roll film develop without agitation?

If this is a good idea, the obvious problem is calculating a new processing time due to the fact that it would be continuous and therefore higher energy agitation compared to the intermittent agitation with hanger processing? Can anyone help with this time calculation?

Thanks.

Tim

[Heespharm]

Yes you can just make sure you do some tests.... Some of the ridges may have sharp edges that can scratch your negative... Times are well published for most films under "constant agitation"

[Jay DeFehr]

I've developed many sheets of film in the Unicolor drum. Mostly, it's worked well, but I have had issues with some developers, when I didn't use a pre-soak. The drum can't be filled while rotating, and it doesn't fill quickly, so there's an opportunity for uneven development. A pre-soak alleviates the problem, to some extent, as does using a more dilute developer, but I'm always a little nervous about it, and wouldn't trust a very important negative to this method.

[tgtaylor]

If it's Kodak film, look in the Tech Pubs posted on the Kodak website where you will find the developing time and step-by-step procedure for rotary processing Kodak films from which you can extrapolate.

For non-Kodak films the recommendation is to reduce development time by 10% to 15% of the published time. I recently rotary processed Acros using the mid-point of that recommendation (12.5% reduction) with excellent results. i don't use a presoak when rotary processing (Jobo CPA with lift).

From my limited experience I have found the published times on the digitaltruth site to be for intermittent or non-rotary processing.

Thomas

[Lynn Jones]

It is the most even processing that you can get with still film, its almost as good as motion picture "spray processing" (yes I've done both).

Lynn

[sully75]

digital truth recommends starting with 15% less than their recommended times if using rotary processing.

[atlcruiser]

I do it all the time in a big JOBO tank on a unicolor powered roller. I have only had an issue once and I think that was really my fault.

it took a little while to get the time right but much of the info is out on the web and I only needed to fine tune a bit.

I find it very quick and easy with almost perfect results

[grahamcase]

I literally just finished doing this, about 20 minutes ago. I'm the "throw caution to the wind" type, and just processed TMAX 100 in Rodinal at 1:50 for the posted time of 12 minutes, and it seems fine. I guess I'll be able to tell better when I (eventually) get to contact print it. I did this as a test, and am very happy with the results - this is way better than standing in the dark for hours tray processing one sheet at a time.

The Unicolor base I was using alternates directions every 3-5 seconds, or so. I'm guessing, since I never actually timed it, but it certainly was not constant agitation in one direction, it was constant, alternating agitation.

Oh, I also pre-washed, as I am a firm believer in always pre-washing any film larger than 135...

Shoot a test shot, and see what you think of the results.

[lenser]

Thanks for all the great input, everyone. I tested the bases action last night and discovered it is auto reversible, so I plan to do some shooting this weekend and give it a try.

This is an 8x10 print drum, so not too long, but are there any issues with tracking? Should I strap on a couple of big rubber bands or "O" rings to limit that possibility?

[John Kasaian]

You want to use a print drum, not the film drum for developing sheet film. I use one for8x10 panchro film and trays for ortho, and I've been very happy with the results. The surface you work on has to be flat oryour drum might roll away. I use those thick purple rubberbands that come on broccolli and asparagus as a flange of sorts to help keep the drum from abandoning ship.