Jobo edge density film problem

[John Powers]

I am getting overdevelopment or high edge density on the film edge opposite the notch. This is the 7 inch side of 7x17 film. The other three edges are fine. Can you offer suggestions how to eliminate this problem?

I am using 7x17 HP5+ film, Rollo Pyro developer from Bostick & Sullivan. I develop two sheets at a time of the same image bracketed 2 stops. The notched edge is always loaded at the top or lid end of either of two 2800 series drums. Emulsion faces to the center of the tank. The problem happens in either drum. I have ten film holders and the problem exists which ever film holder I use so I doubt it is a light leak. The higher density is roughly ¼ inch to 3/16ths”. Some times I can burn it out in printing with approximately 100% burning time or twice what it takes for the rest of the print.

I have been using Rollo Pyro for at least five years, but this seems to be a recent problem.

I am using a Jobo CPP-2 serial # 13391. I use a five minute prewash with the sodium metabolite that comes in the Rollo Pyro kit. This is ¼ teaspoon in 500 ml water. The water is 70 degrees F or 21.1 C. Development time is 6 minutes. In an experiment to reduce agitation I have been decreasing the rotation speed from 4, to 3, to F to the first notch beyond F. This seems to have made the problem worse.

Any help appreciated. Ask if you have questions.

Thanks,

John Powers

[keith schreiber]

Hi John,

If I read your description correctly, the area where you are getting higher edge density is the edge closest to the bottom of the drum i.e. farthest from the lid. Is it possible that you are inserting the film all the way to the bottom? If so, there might be a bit more rotational turbulence at the end of the drum than elsewhere. If your drum is a 2850, there is about 21 inches inside from end to end. If you are not already doing so, try positioning the film so that it is centered rather than inserted all the way.

~ Keith

[John Powers]

Hi John,

If I read your description correctly, the area where you are getting higher edge density is the edge closest to the bottom of the drum i.e. farthest from the lid. Is it possible that you are inserting the film all the way to the bottom? If so, there might be a bit more rotational turbulence at the end of the drum than elsewhere. If your drum is a 2850, there is about 21 inches inside from end to end. If you are not already doing so, try positioning the film so that it is centered rather than inserted all the way.

~ Keith

Thank you Keith. You are correct. I insert the film all the way to the bottom of the tank. That is where the problem is on the film. I will try the next batch with the bottom edge off the bottom of the tank by centering the film in the tank.

Thanks,

John

[Larry Gebhardt]

You might try flipping the film around (notches to the bottom). That would let you see if it's a light leak in your camera. My money is still on turbulence however.

[John Powers]

You might try flipping the film around (notches to the bottom). That would let you see if it's a light leak in your camera. My money is still on turbulence however.

Good thought. I can combine both ideas in one development.

Thank you.

John

[Lachlan 717]

I develop 7x17 in Jobo 2xxx drums as well and don't have this issue (using Tetenal Ultrafin 1:20).

FWIW, I make sure that the film is centred, not bottomed.

[sanking]

I don't know the exact cause of your edge density problem but I have spent a lot of time trouble shooting this issue with ULF film developed both in Jobo print drums and in other print drums, like Unicolor and Beseler. The most likely cause is some type of rotational turbulence around the edges, as Keith Schreiber suggested, most likely introduced by a rib, dividers or uneven spots inside the drum, .

What I have found to be the Number 1, Number 2, and Number 3 solutions to this problem are, 1) weaker dilution and longer development time, and 2) slower rotation, and 3) lift the drum very early in development and rotate it up and down, and repeat this every two or three minutes.

The three solutions have worked for me with both Pyro staining developers like Rollo Pyro and Pyrocat-HD as well as traditional developers like D76.

Sandy

[Lachlan 717]

Just to add a little more to my earlier post, I prewash (3 minutes and then another 2 in clean water), and set my Jobo to "F" speed.

[Andrew®]

Hi John,

I've also had the same issue. As Sandy has mentioned, lifting the drum off every 3-4 minutes and inverting a couple of times has resolved the issue.

Andrew

[John Powers]

Thank you all I plan to try these suggestions in my next developing probably tomorrow. I will report back.

John