Question about Jobo/Rotary Film Processors

bvy · Mar 12, 2016

For those of you with Jobo or Unicolor film processors, I'm curious -- do the film edges get overdeveloped? I've been experimenting with rotary processing on a Unicolor (reversible) motor base, but I'm using regular Paterson reels either in a tank or a Unicolor print drum. This works just fine -- good even development -- except that the edge of the film that sits in the tracks of the reel gets over developed (see contrast- enhanced picture). Since I'm doing some work where the film gets exposed all the way to the edge, this is a concern. It also creeps into the edges of regularly exposed frames as well. I've only experimented with 120 thus far.

Is there something special about Jobo or Unicolor reels such that this isn't a problem? I've looked at pictures, and I'm not seeing it. Or is it just the nature or constant rotary processing and agitation? Thanks.

Alan9940 · Mar 12, 2016

I process most of my film on a Jobo CPP-2 using Expert Drums for LF and 2502 reels for 120. In 20+ years, I've never noticed any increased density near the edges of any film.

MattKing · Mar 13, 2016

Are you sure your tank is level? If, not, one edge may get more development then the other.

mexipike · Mar 13, 2016

I don't know anything about Jobo processors but in looking at your scan it seems like only the area that isn't normally exposed which would be the negative border with info is lighter. Could this possibly have something to do with the capture or the emulsion? What camera are you exposing this film to the edges with?

RobC · Mar 13, 2016

looks a bit odd. I can't see it on bottom of image and top edge it seems to only be there in the highlight of the forehead and not all the way across.

It could be film reel contamination with chemical or photoflow from last usage. I do not think its due to development flow pattern or surge.

Was film tank on its side when you filled it or was it upright. If it was on its side, was it rotating.

Diapositivo · Mar 13, 2016

MattKing said:
Are you sure your tank is level? If, not, one edge may get more development then the other.

I also think the OP might have a problem with levelling.

I have never had any problem of this kind - uneven development - with my Jobo rotary processor and Jobo reels and tanks. I use 135 and there are perforations at the edge, but it's slide film and I think I would have noticed uneven development.

I did notice, though, that levelling it by taking the measure on the red edge of the upper tray does not lead to perfect levelling. I measure the levelling at the tank when the arm is down.

Vaughn · Mar 13, 2016

As a possibility -- perhaps it is not over-development, but rather incomplete fixing. I have had that issue with 120 in steel tanks. I solved it by more agitation during fixing. In your case the film near the reel tracks may not be getting fresh fixer.

bvy · Mar 13, 2016

It can't be leveling. I should have provided more details, as I'm kind of improvising while I see if this works for me. The reels go in the Paterson tank, and the tank sits on its side on a roller base (see photo). Unicolor makes a drum and reels specifically for this, which I'm looking at, but it's the same in principle.

Also, the film (120) was cut and taped into an 8x10 holder, so it should be exposed evenly from edge to edge.

MattKing · Mar 13, 2016

bvy said:
It can't be leveling. I should have provided more details, as I'm kind of improvising while I see if this works for me. The reels go in the Paterson tank, and the tank sits on its side on a roller base (see photo). Unicolor makes a drum and reels specifically for this, which I'm looking at, but it's the same in principle.

Also, the film (120) was cut and taped into an 8x10 holder, so it should be exposed evenly from edge to edge.

View attachment 152420

Actually, it can be due to issues with leveling.

If the base itself isn't level, there is more developer near one end of the film than the other.

How much developer are you using?

I do something similar with a Paterson tank and a Beseler roller base. But I've gone back to doing inversion agitation for all but the first 30 seconds of the development stage.

I put enough developer in to permit inversion agitation - one litre for that size of tank (if it is the one I think it is). I use HC-110 replenished, so the volume isn't a concern.

I use the roller base for all of the rest of the development process.

Photo Engineer · Mar 13, 2016

I have had no such problem with either of my Jobo processors and any of my tanks and reels from 35mm to 4x5. I do see that you are using more than a standard frame for your pictures though.

It looks like some sort of flow problem around the flanges. This would indicate that the film may be stickiing to the flanges or the flanges may be extra narrow. IDK.

PE

Bob Carnie · Mar 13, 2016

I think the reels are the problem and switch to the Jobo reels. I have never seen this problem and I have been using Jobo process for over 20 years..

MattKing · Mar 13, 2016

Bob Carnie said:
I think the reels are the problem and switch to the Jobo reels. I have never seen this problem and I have been using Jobo process for over 20 years..

I got nice even development with the AP (Paterson clone) reels and my Beseler rotary base when I did this with continuous rotary agitation throughout. I switched back to inversion for the development stage because I had trouble with the rolls wandering and overlapping when I tried to load two 120 rolls on each reel (without taping them together).

Bob Carnie · Mar 13, 2016

the minus density on the mans head looks about the same thickness of the reels.. This can be a very simple solution that will drive the OP nuts getting to that point.

I also recommend complete inversion of any rotary process by hand in the first 30 seconds if any worry about complete development.

RobC · Mar 13, 2016

You are aware that paterson tanks were't designed for roller bases. The 4 reel tank and I think the 2 reel tank don't have parrallel sides. They are slightly conical in shape and that means that if you put it on a normal rotary base and the base is leveled, the tank will not be levelled and the narrow end of the tank will have deeper/more developer in it than the wide end. Measure your tank diameter at top and bottom ends to verify.
And theoretically, it means the wide end gets more agitation than the narrow end since it moves a longer distance in the same time, but the reel doesn't. Go figure.

So this could be a contributing factor but not conclusive.

MattKing · Mar 13, 2016

The latest Super System 4 tanks do have parallel sides - on the outside. And the inner sides are very close to parallel.

To the OP: what volume of developer are you using? I expect that you will have no problems if you use at least 500 ml in the two 120 reel tanks.

RobC · Mar 13, 2016

my 4 or is it 5 reel tank doesn't.

bvy · Mar 13, 2016

Thanks everyone. Yes, I'm aware Paterson tanks weren't designed for this, but as mentioned, the sides are parallel, and the base is level. Mechanically, it works just fine. In any case, I was doing two inversions by hand every minute, followed by switching the direction of the tank on the base.

I agree with PE that it looks like a flow issue, which makes me question the design of these reels versus Jobo reels.

I like the idea of inverting by hand for the first 30 seconds or so.

I'm using about 600ml of solution which is about half the tank capacity. I wonder if I should be using more solution.

MattKing · Mar 13, 2016

RobC said:
my 4 or is it 5 reel tank doesn't.

Are you excluding the one centimetre ridge at the top?
I don't have a caliper available to me that can confirm the parallel sides, but a level indicates that it is certainly at least very close.

MattKing · Mar 13, 2016

bvy said:
Also, the film (120) was cut and taped into an 8x10 holder, so it should be exposed evenly from edge to edge.

Could it be from the tape you used?

RobC · Mar 13, 2016

MattKing said:
Are you excluding the one centimetre ridge at the top?
I don't have a caliper available to me that can confirm the parallel sides, but a level indicates that it is certainly at least very close.

ridge at top excluded.
Turn tank upside down and take a piece of string or cotton which goes all way round and pinch it together tight around tank with fingers and try and slide it down tank. If not parrallel you will feel string pulling through your fingers and staying tight around tank. Then slide it back up and it will become loose. Thats what I just did. My tank IS slightly conical.

bvy · Mar 13, 2016

MattKing said:
Could it be from the tape you used?

Thanks, but no, I'm using double-sided tape.

bvy · Mar 13, 2016

This is conjecture: With the tank half full, the film is in the solution about the same amount of time that it's not in the solution (i.e. when it's rotating above the solution level). So I wonder if the tracks of the reels are retaining developer during an entire rotation cycle causing increased development along the edges? If so, could a tank filled to, say, 90% capacity solve the problem? Just collecting thoughts as this will likely be my next experiment.

MattKing · Mar 13, 2016

Do you see the same effect on a 120 roll that was exposed normally - in a 120 camera?

The sharp demarcation between the darker and lighter parts make me think that there is something other than enhanced developer activity happening here.

bvy · Mar 13, 2016

These were throwaway shots from a Brownie -- frames from two different rolls of Acros 100. They were processed in the same tank.

This film was rotary processed as described above. Same thing.. It's less obvious on the right side, but the I think that has more to do with the overdeveloped area landing in the gutter (the frame's not perfectly centered on the film).

This film was processed conventionally (using lateral agitation, 60 seconds initially then every minute).

RobC · Mar 14, 2016

are you usimg photoflo on your negatives by putting film still on reels into it?

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