Help me with this Paterson Orbital stripe

[Minhhich]

Hi guys,
I have some experience with developing 35mm and MF using Paterson tanks and recently bought an Paterson Orbital processor for 4x5. Following advices from people I put domes of epoxy onto the base of the processor to keep the film from sticking to the base. After processing 2 sheets of Shanghai gp3 film in one batch using 450mm solution (which i tested to cover the film without agitation). I found out there are identical black stripes in the middle of the film see image below. I suspected these are caused by the "wings" on the lid of the processor touching the film during the process. What should I do to avoid this? Is it because I used too much developer? I used 450mm solution of 1:100 R09. Rocking the tank manually for agitation for the first minute and let it stand for 1h. Thanks
http://farm6.static.flickr.com/5107/5810852296_688d6b78c3_z.jpg

[Colin Myers]

Hello,
For efficient trouble free processing og sheet films in the Paterson Orbital processor, the fins or ribs, need to be removed.
How high are your epoxy domes? You only need to just lift the sheet of film away from the base. I use tiddley wink, style discs on my processer and I guess these measure some 1 to 1.5mm in thickness. Hope this helps. If you need a photo of a lid sans the ribs, I am happy to forward one
Colin Myers

[Pete Watkins]

Hi,
Cut the wings off and make sure that there are no rough bits left and reduce the amount of liquid used to 300mm. As long as your epoxy domes arn't too high (about 3mm is O.K.) this should work well. Works for me.
Pete.

[Minhhich]

Thanks for your response. I will try to cut the fins off. The domes I have are about 3mm height. I wonder if 300ml solution would be enough for stand development?

[Minhhich]

Colin, please send me a picture of the lid with fin off

[Pete Watkins]

Sorry Minhhich but I only use it for contstant agitation. Just stand it on a flat surface and pour some water into the thing until you're convinced that all four sheets (if you're using 4x5) would be covered. 300 mm ensures that the film is always in the liquid on my setups. I wouldn't think that you need either the motor base or the manual base for stand development.
Pete.

[Ash]

Still got the fins on mine and I've used 400ml no problem. I cut grooves into the base with a knife. I leave it to stand.

If your sheets are touching the fins then they're floating too high.

[ic-racer]

Black stripes in the middle of the film??? You print has a black stripe, so there should be a lucent area on the film. Is that so?

[Ash]

IC, I think it's where the emulsion is sliced by the fin, but is still wet enough to repair itself and give that soft edge around it. May be wrong though.

[EdWorkman]

I got a similar stripe pattern on prints.
i had exposed several sheets and developed them all at the same time.
Apparently the agitation was insufficient to move the developer near the center far enough - as if the zone of exhausted developer "overlapped " as it shifted back and forth, never allowing fresh developer on the overlap zone.
As those stripes were white on a print, they would be clear on a negative, and thus similar to your case.
Ever since that I have used oversized trays and no more than a coupla sheets at one time and have had no problems with intermittent rocking for agitation. And from situation where i was attempting to multi-task during development, it seems the initial 20-30 seconds out of 2 min is the important part- forgetting to agitate the remainder seems to have unnoticeable effect seconds.

[Ash]

I spoke too soon!!!! For the first time ever it has appeared on my 5x7's. I'll be lopping off the fins tomorrow.

[Minhhich]

Hi, I tried some shots today and developed with less developer solution of 150ml at 1:25 for 10 mins constant agitation on manual base. I agitate at 1 revolution per 3 secs. The negative does no more have stripe but now being uneven. Ill try again after my exams agitating by rocking back and forward and left to right instead of the base. I didnt presoak, do I really need to? Note that the 2 dark top corners are vignette from shift up too much, not under developed as I checked on the ground glass when taking the picture.

http://farm3.static.flickr.com/2397/5813103827_6946576ba6.jpg

[Colin Myers]

Hello,
As requested here are a couple of snaps of one of my Paterson Orbital processors.
The shot of the tank base, clearly shows the "tiddley wink" style buttons, to lift the film clear of the base and all four film/paper seperators are in place. The other image shows the lid of the tank, with fins/ribs removed.
Even if your sheets of film do not physically touch the fins or ribs, their presence will disturb or interupt the flow of developer causing other anomolies.
Colin

[Cor]

Minhich,

A few remarks on the Orbital, I had to remove the fins to avoid stripes.

I have thus far only processed 8*10, I have not done anything to the bottom, but I pre-soak for 5 minutes, and listen if the film moves around, never a problem with the back of the film.

I did have a problem with a "circle" just like in your image upper left. I had it dead centre though.It was with a second negative, and although I paid attention to careful drying the Orbital, it might have been a drop of water. But I also used out dated film.

Anyhow, next time when I process a second sheet, I'll fill the Orbital with water, and slide the film in the darkroom in the filled Orbital, that should in theory rule out water drips.

Best,

Cor

Hi, I tried some shots today and developed with less developer solution of 150ml at 1:25 for 10 mins constant agitation on manual base. I agitate at 1 revolution per 3 secs. The negative does no more have stripe but now being uneven. Ill try again after my exams agitating by rocking back and forward and left to right instead of the base. I didnt presoak, do I really need to? Note that the 2 dark top corners are vignette from shift up too much, not under developed as I checked on the ground glass when taking the picture.

http://farm3.static.flickr.com/2397/5813103827_6946576ba6.jpg

[Pete Watkins]

Minhhich,
I use 300 ml of solution and that ensures that the negative/ negatives are in solution at all times. Personally I think that 150 ml is too little.
Pete.

[cjbroadbent]

Pete, I was getting uneven with 350ml - must be something to do with slosh and fluid dynamics.
Since 8x10 or 4 4x5s exhaust 150ml (Steve Anchell) I do a second 150ml at half-time.
Never had a problem since. I do prewash though.

[Pete Watkins]

Chris,
I use 300 ml of D-76H 1-1 and put it on the electric rotary base (I used the manual base before). About 6 times during the development cycle I lift the tank off the base and rock it side ways and backward and foreward manually. I use Foma film that gets slagged off here on a regular basis and I've never had a problem. I do 8x10 (1 sheet at a time), 5x7 (2 sheets at a time) & 4x5 (4 sheets at a time). I also do 2x2 minute prewashes, but I've developed Ilford film without the prewashes (they advise against it) without any problems.
Pete.