View Full Version : processing 8x10 (B&W) with unicolor motor base and tube

15-May-2011, 10:59
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?



15-May-2011, 11:11
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
15-May-2011, 11:44
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.

15-May-2011, 12:26
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.


Lynn Jones
16-May-2011, 15:53
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).


16-May-2011, 18:38
digital truth recommends starting with 15% less than their recommended times if using rotary processing.

16-May-2011, 20:32
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

17-May-2011, 00:30
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.

17-May-2011, 07:07
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
17-May-2011, 10:20
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.

Lynn Jones
17-May-2011, 15:59
In drum or continuous agitation in trays, reduce developing times by 15 to 20 %, in the secondaries leave the times alone.


17-May-2011, 16:22
In drum or continuous agitation in trays, reduce developing times by 15 to 20 %, in the secondaries leave the times alone.


Although Lynn has more experience in this than I do, I wouldn't recommend going beyond a 15% reduction on your first try.

Normally processing B&W by the ol' hand immersion and more recently the dip-n-dunk methods, about 10 days ago I was confronted with the same question when I decided to rotary process some 4x5 Acros negatives. After consulting the Kodak site, Fuj Guide and digital truth, I decided to use the time as published by Fuji and digital truth with a 12.5% reduction (the mid-point of the Kodak recommendation). Here is the result:


The above is not a scan of the negative but a scan of the 8x10 print on Ilford WT RC Glossy paper. Besides choosing the exposure for the paper, the only manipulations used was to dodge the right and left arches to even the density in those location. Otherwise it is basically a straight print of the negative. That said, I plan to give a 15% reduction on the next batch to try and tweak it but wouldn't want to go any further than that with Acros.


David Lobato
17-May-2011, 20:28
I process 8x10 b&w sheets all the time with a Unicolor reversing roller base and 11x14 print processing tubes for 2 8x10 sheets at a time. My biggest problem is the old drums leak and the lid gaskets get old. One drum I have does okay though. 8x10 print drums work okay for one sheet at a time but be sure the plastic rib that goes lengthwise inside is in place or else the sheet sticks to the inside surface. The drums are fairly easy to load in the dark. I've had about 95% success with the roller base and print drums. A water presoak helps with more even development.

8-Aug-2011, 18:31
Just over the weekend I had my first "mishap" with rotary development. I have been developing minus 15% of posted times, and have been doing well developing FP4+ in Ilfosol 3.

I have Unicolor drums that hold two 8x10 sheets at a time, and a uniroller base.

On Saturday, I developed in Clayton F76, and got slight over development and splashing on the sides of my film that were on the bottom of the tank (well, when the tank is oriented correctly horizontally).

Here is one of the shots (testing out my 14" CE lens)


Any thoughts? Maybe just a bad developer choice for rotary?

9-Aug-2011, 19:11

I've perfected drums---always use a pre-soak---the BEST pre-soak is to put the tank vertically and fill it with a tiny hose---like the kind that you buy at walgreens with the litte showerheads on them....fill to top and leave the water pressure get all the water in behind that film to get that backing coating dissolved---you can make your own aftermarket gaskets with hobby thin foam---these NEVER leak again--they are tight, but work well when you do it right...and have to be held in place with tape...do it 10 times and your an expert

most important is that pre-soak----if you dont' want to fill a tank with the LOTS of water it takes, then fill it on the roller with LOTS of water to ensure pressure gets the water UnDER the film---pre-soak water should be EXCESSIVE...for the 11x14 drums I use no less than 24 oz water for pre-soak---run for 5' and then rinse about 4x1' till all the color is gone...

then you can develop with minimal chemistry (12 oz in that size for me for 2 8x10s' or 1 11x14) and no headaches at all.....

for the smaller 8x10 drums I use 6 oz chemistry per sheet (you need that much to get over the "hump" in the middle of a an 8x10 sheet---and for pre-soak it's 12 oz....that seems to provide enough liquid depth in the bottom to force the water in back of all the nooks and crannies.

I was plagued with marks till I started PRESSURE pre-soaking----you can use a LOT of developer also to get back there, but that kind of defeats the purpose of tubes---to use less chemistry.

10-Aug-2011, 03:26
But, wouldn't the film sticking to the side just not allow you to wash all the anti-halation layer off? It should not affect development. Also, my overdevelopment is strictly on the opposite sides of the two negatives I developed, meaning that the cause has something to do with the developing process, or how I fed the developer into the tank - at least, I would think so.

And I know that my film wouldn't stick to the sides of the tank on the side of the negatives that have the problem; the are held up on that end in a similar way the 8x10 tanks have a 'hump' in the middle - there is, what is like, a V sitting inside another V to hold the film in place. A flat text model of this would look something like: _1_\_2_\/_2_/_1_ (numbered for convenience). the filmsheets fit into slots 2, meaning the outside V forming slots 1 bumps each negative out from the side of the tank.

I'll take another couple of shots soon, and test develop using my Ilfosol 3, to see if things go back to normal.

Robert Skeoch
10-Aug-2011, 05:15
I've used this method for years on 8X10. With 8X10 I could do two sheets in a drum.
Now I've switched to 4X10 and use a smaller drum but have to do them one at a time. I think there are spacers which would allow me to stack two sheets but I don't have any.

I use Delta 100. I use ID-11 1:3 for 14 minutes. I use 500ml of chemisty. No pre-soak but it wouldn't hurt.

If the scene was very contrasty I use less time, more for flat lighting but usually 14 min. Haven't had any problems with this method recently.

-rob skeoch

10-Aug-2011, 07:10
the film sticks where it touches the edges if you don't get the back layer off--once the back layer is off, you're ok

the only way I've found to reliably get that layer off is to use water pressure (height of standing water in the tube) to wedge between the film and the drum --ESPECIALLY at the hump for 11x14!!!!!--that's a problem area--it presses on there and the back layer won't come off. once it comes out...rinse rinse rinse till the bubbles and smell are gone and you're ready to develop without fear of sticking marks.

Unless you use a LOT of developer--which will provide the pressure of it's own.

the problem really shows itself in some other drums with larger flat spots....and particularly for 11x14 and larger film---it takes a LONG time for the liquid to migrate behind the filmi...8x10 with like 10' development time you'll probably only have sporadic problems with the drum your using....but why take a chance? soak it and be sure EVERY time.

29-Aug-2011, 10:57
I just wanted to pipe up again with regards to my Clayton F-76 experience in rotary tanks:

I tried a second time to develop some negs in F-76 in rotary, and again I got inconsistent negatives, so I've given up on F-76 for rotary development. My experience with Ilfosol 3 has been nothing but good! I have not done any tests, or densitometer readings, but to the naked eye, there are none of the inconsistencies that I've found in the F-76, which is sign that it works better, at least to me.

My dev time with F-76 was something higher than 5 minutes, while my Ilfosol 3 times go form 3:36 for normal development, to 2:32 for attempting to compensate for overexposed highlights (I would call it N-1 development, but it's really me just under developing 30% after doing some rash "zone" readings). 3:36 is an adjusted time for rotary development, 15% shorter than the time listed on Digital Truth Massive Dev Chart.

Other than the developer, my technique has always been the same, including the pre wash, so it doesn't seem like my prewash is the problem.