Help me with this Paterson Orbital stripe

[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.

[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.

[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.