Water strip problem with Jobo CPA C41 process

[ahock]

I'm processing C41 film with Jobo CPA (using Multitank 5, and NO LIFT) machine. But there have water spot or water strip problem on my film.
Here is the image:

I also have upload the whole roll of film at here:
http://kienhockblogspot.googlecode.com/files/water%20strip%20-%20APUG.zip (size: ~5mb)

Please note that the direction of the water strip is perpendicular to the rotation direction of Jobo CPA.

Here is the procedure of my process:

Dry pre-warm 15 minutes (about 10% of the drum submerge inside water )
Developer 3 minutes 15 seconds
Bleach 6 minutes
Wash 2 minutes
Fix 8 minutes
Wash 1 minute
Stabilize approx 3 minute
soak with photo-Flo (30 seconds) and Dry


I try to keep out from water strip with the following methods:

1. Purchase a new Jobo processing drum with lid. This doesn’t help at all. The water strips still happen occasionally.

2. Dry pre-warm without submerge the tank inside water and shortened the treat duration. I suspect it is water leak causes the problem. But, this doesn’t help at all.

3. Presoak the film before pour in developer. I can’t found any water strip on the film.

1 minute Presoak can solve the problem of water strip. But, I prefer to do it with dry prewarm.


Please give me some suggestion. Thanks~

 

[largeformat pat]

How much chemistry are you using? I would try a larger amount of developer. Not excessive just more than recommended. People will always say that is to expensive. However can you re shoot? Doesn't matter no casual the shot.
Pat

 

[ahock]

I purchased Kodak C41B from local studio (Taiwan). I have to buy 1 case each time. There have 4 set C41 chemical inside and can make 40 litres replenisher. It cost me ~USD80 for 1 case.
I need to add starter to make the replenisher into develop working solution. 40 litres replenisher can make ~ 48 litres working solution.

 

[L Gebhardt]

I would also bet there is water getting into the drum during your prewarm step. If a pre soak works, why not go with it?

But just to test put a dry drum in the processor with no film in it. After 15 minutes thoroughly dry the outside and then open it to check for water. That should tell you if water leakage is the issue.

 

[ahock]

Thanks, Gebhardt!!

In the beginning, I also bet it is water leak issued. I also check this with put a dry empty to do wet prewarm. After 15 minutes, there have some drop of water inside the drum. That is why I go to get a new drum. I also check the water leak trouble when I receive this tank. The performance is quite good. I thought I will be in heaven after replace the old drum. However, I still got water strip on my developed film.

Then, I exclude both dry/wet prewarm methods from my process. I try to use conductive method to do the prewarm job. I use an aquatic pump to pumping water from my Jobo CPA tank. The drum was surrounding by the water pipe which have hot water pass though. Here is the figure:

Unfortunately, conductive method also has water strip trouble.

Let me summaries the story:

1. I'm using Jobo CPA + Multitank 5 doing C41. I can get water strip problem occasional. Sometimes all of the films are perfect, no water strip at all. Sometimes some of the film have water strip.

2. I have try presoak to eliminate water strip issue and this is quite helpful. I'm not very sure whether presoak can eliminate water strip issue or not. It is because this issue was happened occasionally. I need time to prove it.

3. The flow direction of the water strip is perpendicular to the rotation direction of Jobo CPA. This phenomenon hint that it is not happening during the drum under rotation.

Can anybody tell me the reason of all of these phenomenons?

Thanks a lot~

 

[Photo Engineer]

You have a water leak the instant that the drum is placed on the gear. The only solution is a water prewet.

PE

 

[ahock]

PE,
Thanks for yours comment!!!
However, due to some reason, I really doubt it is cause by water get in the drum before I pour in the developer. The most important evidence is that the flow direction of the water strip is perpendicular to the rolling direction of the motor. Moreover, process without presoak or prewarm also have this phenomenon occasionally.


I think of this question the whole night. I also take off the lid and pour in water to see the flow pattern of the water. I found out one interesting fact. The water inside - out hole is very close. Here is a picture to explain this:

These two holes are place very close together; water can get inside the drum with the pour out gap. If I pour in developer too quickly or too nervous, developer will full and flow over from the pour out gap. Developer come in from the pour out gap will cause the streak on the film. I need about 10 seconds to pour in all of the solution and another 3 seconds for put the drum on Jobo CPA. It takes another 3 second to distribute all of the developer to the film surface.

I guess may be this is the reason cause the streak.
Please give me some comment. Thanks~

 

[fotch]

Why don't you try the prewet just to see if is solves the problem. Sometimes the simple solution is the solution.

Good luck.

 

[Photo Engineer]

I think, as I said before, that the problem is due to a water leak just as the tank is attached to the cog gear. No matter what you do, only a water prewet will solve the problem. I took a Jobo tank like that and put in some water and then sealed it and turned it upside down. It leaked around the red ring. So, if the water level in the Jobo is high enough, it will leak water into the drum.

PE

 

[ahock]

PE, fotch,
Yeah. I will try to do prewet next few round to see the effect. Thanks~

 

[L Gebhardt]

I have never used the drum with them filled vertically, so that may be the issue as you mention. I don't know if you can get a lift for the CPE, but if you can that may solve your issue as the drums are filled while rotating. With the CPP and ATL I have never seen this issue, both using a lift. Maybe try using a funnel with a long tube to fill rapidly and direct it down the inner tube of the drum.

Are you absolutely sure the drum is dry before loading the film?. Have you taken apart the funnel to dry it?

 

[ahock]

Gebhardt,
I'm using a dryer to dry my drum, so I'm very sure the tank is dry before I use it. I also use a hot water pipe to do the prewarm with the drum is stand. With this prewarm method, the lid will not touch the water untill pour in deverloper and put it on JOBO CPA. So, it's not possible have any water leak in this situation. But, I still can get water streak at the upper rolls of film. The film located at the bottom is always safe.
Yes. I'm going to use a funnel for pour the solution. A lift may be is a better solution for 2500 series drum.

 

[Pupfish]

Looks to me like the film is sticking to itself either or in a reel or sheets on the tank.

Don't try to cram 2 rolls of 35mm on a Jobo reel, be careful loading 120, and use proper reels instead of paper drums or tanks for loading 4x5 sheet films.

 

[ahock]

Thanks all of you~

I have try to pour the solution with a funnel. Please refer to the picture below:

I develop three times and get no strip with this method. I think C41 is a more vigorous reaction. It would be nice if we have a lift to do the job. Otherwise, we must take good care when pouring the develop solution.

I try my best to DIY a "Lift" for my Jobo CPA. I use a funnel connect with a "L type" pipe. I also use a cog lid to make this work. Here is the figure how I pour in the solution.

A little bit Clumsy, but really work~