View Full Version : Combi-plan causing uneven development

7-Nov-2005, 18:18
I have used a Combi-plan for 4 years, and rarely, if ever, experienced uneven development. Now it is happening all the time and getting worse. The problem is visible along the edges where the film sits in the channels. It appears that there is slightly less development within the channels and slightly more in a pattern spreading about 1/2 a centimeter in parallel to the channels. It is worse in some negatives than others. What stumps me is why it is getting worse. I have not changed development dilution, fixer, stop bath, or film type. Though I have tried changing my agitation technique, with no effect. My only guess is that there is some kind of invisible build up of LFN, developer or fixer residue or something similar that is effecting the flow pattern. Anyone have a similar problem? I would appreciate your guidance. Thanks, Phil.

7-Nov-2005, 21:31
I would give the film holder a thorough clean, to ensure all residue is removed, and test again.

whilst you have not changed chemicals or film it is possible that the manufacturer has changed them without you knowing about it, as they often do.

Water quality could also change, but I think it would have to be quite a severe change to affect devolpment like that.

7-Nov-2005, 21:34
also check your mixing jugs/utensils which could be contaminating the developer etc. Have you been using them for mixing anything else?

Gudmundur Ingolfsson
8-Nov-2005, 03:32
This sounds to me like someone that has been putting a wetting agent like
photoflo in his tank or on his inserts. A wetting agent should never be allowed
to come into contact with processing utensils; reels inserts or even tanks. This
will lead to uneven development.

8-Nov-2005, 06:57
I do use a wetting agent, LFN. Is it possible to get rid of or reduce the buildup of wetting agent?

Thanks, Phil

Gudmundur Ingolfsson
8-Nov-2005, 08:26
Try to soak the insert and the tank with acidic acid
for a few minutes and then wash with as warm water as
the tank can take, without melting.

8-Nov-2005, 08:33
I never experienced build-up from Photoflow. It's just a detergent. But then, I always clean the equipment thoroughly after use.

Bob Salomon
8-Nov-2005, 09:18
"I have tried changing my agitation technique, with no effect"

The Combi-Plan was designed specifically for inversion agitation. As such it was made so that when it has the proper amount of chemistry in it there is still some air space so the chemistry can "flow". For 45 the recommended amount of chemistry is 36 oz. The recommended agitation procedure is to invert the tank and wait till the chemistry stops moving and then reinvert it. If necessary to fulfill the required agitation time repeat the inversion and reinversion.

Periodically rap the bottom of the tank on the table to dislodge any air bells. At no time shake or use other agitation procedures and do not completely fill the tank and remove the air space.

Is this the procedure you are following? If so, and you still get a pattern are the curved faces of the film guide on the side both facing in? The straight sides for glass plate use should be both facing out. Is your film retaining clip broken?

If you do not have the directions for the tank I can email them to you.

8-Nov-2005, 10:14
Mr. Salomon, thanks for responding. My inversion procedure is almost exactly as described, except that I did not know to wait for the chemistry to stop moving before uninverting. The change in agitation that I described was the reduction of interval from 2 inversions every 30 seconds to two every 60 seconds. I use 1050ml of developer as recommended and I rap the tank bottom. The curved faces are in the inside as you recommend, and the clip is intact. Is the use of surfactants such as LFN not recommended in Combi-tanks? Thanks, Phil.

Bob Salomon
9-Nov-2005, 06:57
We have had no reports of problems with Photo Flow type products so just wash the system out thourghly and then try it again leaving the rinse aid out. See if that eliminates the problem.