View Full Version : Strange Patterns

al olson
9-Apr-2007, 11:31
Does anyone have an explanation as to the cause of the patterns in the accompanying image. These three frames are from the end of a 12 exposure sequence on Ilford Delta 400 that was loaded in a darkroom and processed in Jobo CPP-2 processor with HC-110, dil B.

The first 7 exposures on this roll are good. This pattern has never appeared on any other roll I have exposed and processed.

X-ray comes to mind, but this film has not gone through a security checkpoint since it has been in my posession. Had it been x-rayed prior to prior to purchase, then the question would be: how did the interior frames get exposed without the exterior frames becoming exposed as well.

Furthermore, the pattern appears to be continuous all the way around the roll. I would expect the x-ray to penetrate toward the center and diminish on the far side.

This in my mind rules out x-rays. But then what could cause this problem?

David A. Goldfarb
9-Apr-2007, 11:48
That is pretty strange. It crosses the frame lines, so I don't suspect it's a camera problem. Camera light leaks and X-rays don't fog in this pattern.

Do you have a surface with that pattern in your darkroom? Is it possible that during loading you rested part of the film on such a surface that may have been damp with water or even developer to cause overdevelopment in this pattern?

Terence McDonagh
9-Apr-2007, 11:56
The aliens got bored with crop circles?

Seriously though, airport x-rays usually make a single dark band when I've accidently left them in check bags.

al olson
9-Apr-2007, 12:51
Sorry, I haven't seen any aliens. I do have trolls in my house. So far their mischief has been limited to hiding things and then making them reappear long after I quit looking. I have never seen them do anything destructive.

No, David, I don't have anything around with a pattern like that. It appears similar to the steel mesh that they use for security enclosures. Don't have anything like that in my house, nor at the site where the images were made.

Fred L
9-Apr-2007, 14:44
If it's only the last three frames, I'd be inclined to think film defect. For the life of me I can't imagine what would cause this pattern on the end of the film ? If it happened during processing, the entire roll should be fubarred. Perhaps you should send this to Simon Galley at Harman ?

Just curious (had a few minutes to think about it...), were these frames in the centre of the processing reel or outside ? I'm wondering if maybe you might have some kind of light leak in the tube ? Not familiar with Jobos,do they rock the tube end to end or just spin them on axis ?

al olson
9-Apr-2007, 15:25
Actually, Fred, the pattern continues over the last 5 frames. This is 120 film, so that when I load it onto the reel, the last frames go in first as I unwrap the paper. Thus, the damaged frames are closest to the core of the reel.

My Jobo is a CPP-2 with "the lift" which is coupled to the motor drive via a cog around the light-tight opening. The drum spins on its axis. The liquids enter into and are expelled from the drum through the lift coupling.

I should also mention that the film was exposed in a Bronica SQ-A. I cannot visualize anything involving the film back or camera that could cause this either. The fact that it crosses through the rebate tells me that it is not caused by some reflection coming through the lens.

I have considered that it could have occured during the manufacturing process, but then I would believe that there would have to be other rolls that were affected as well. I have shot 5 other rolls, presumably from the same batch, without a similar problem. It has been several months since I had processed this roll and I have not heard of any similar reports from anyone else.

I have also pretty much ruled out x-ray (see first post) so that I don't think it could have been caused by a shipper. At that point, the affected frames would be at the inner core of the roll.

It is very curious.

9-Apr-2007, 15:35
I'm thinking light leak: note how the lines are sharp on the left but become more diffuse as they move across the film, much as a light leak on the left hand side would cause. However, like you, I can't think of anything that would make this pattern :( ...

Cheers, Bob.

Jim Galli
9-Apr-2007, 15:39
You forgot the center tube in the tank for a second and the reels protected a certain portion more than other parts so you got that pattern from a light shaft going in?

al olson
9-Apr-2007, 18:13
Thanks, all, for your suggestions. Jim, I think you put me onto the cause. I went back to my darkroom and looked down through one of the reels. If you look at it at an angle so that the view goes through both sides there is a crosshatch pattern similar to what you see on the film.

In tryng to reconstruct what happened, I recall that I was processing 5 rolls of 120 using the Jobo 1520 drum with the 1530 extension that will hold 3 rolls of 120 at a time. I am guessing that when the film was lightstruck I was processing two rolls and the roll was in the middle reel.

If I have fewer than 3 rolls I still place the empty reel on top as a dummy. Now if the lid were not tightly down when the light was turned on or the door opened the dummy reel can create the pattern.

Usually I will notice problems like this and recite, "Oh, darn!" a couple of times. I am not sure why I did not notice at the time, but I am convinced that the cause of the problem has been confirmed.

Thanks again!