Uneven processing

[dennis]

I am using a Combi Plan tank & am getting uneven development which shows as a light area more or less in the centre of the neg, vaguely oval in shape. Developer is APH09, 4 films only each time, & the tank is shaken from side to side for about 5 secs per minute. I find if I try to invert developer leaks out. Any ideas, or should I just give up & revert to dishes?

[IanG]

Combi tanks and the similar Yankee tanks are a pain for agitation, you need to be quite vigorous in the way you agitate, also sometimes sheets bow and the gap between them narrows impeding good flow of developer.

I prefer my Jobo 200o tanks (pre Rotatry) which are just like slightly oversized paterson tanks and easier to use, but I use a Yanke for 9x12 format.

Ian

[Paul Mitchell]

I too suffered from uneven development with the Combi Plan until someone gave me a Paterson orbital and I haven't even bothered to take the Combi Plan out of the box since!

Paul

[Tony]

Hi Dennis I suspect everyones got there own favorite way of processing I bought a set of BTZS tubes from the US and have never had a problem, check out Utube and search for BTZS tubes.
Tony

[Lynne Evans]

Hi Dennis
I'm not an expert by any means, but I've not had a problem with patchy development with the Combi Plan tank. However I did watch an experienced professional using one before I took the plunge, which helped enormously. Firstly I discovered that you have to fill the tank up - I had thought that maybe you part-filled it and then agitated to ensure the film was evenly developed, but I was wrong! Secondly he advocated fully inverting the tank slowly along the long axis - not the short one. This means the sheets of film are less likely to become displaced and results in very even development. I was impressed at just how simple and effective the Combi Plan tank is to use. (Neither his tank nor mine have problems with leakage, so make sure the lid is tightly on and the caps in place.)

Hope this isn't teaching granny to suck eggs.

Lynne

[dennis]

Thanks for the suggestions. Does the Jobo 2000 have a spiral like roll film tanks, & is presumably only available s/h? Lynne - I do fill the tank, but no matter how hard I tighten the top spout it still leaks if the tank is inverted. I'll try again, but it is bit annoying to waste film & time with unusable negs at the end.

[IanG]

The Jobo 2000 series tanks do have a centre column, they are designed for inversion agitation each spiral taking 6 sheets of film. I have the 2 of the larger versions taking 2 spirals each, they were made in the 70's and very early 80's but replaced by the ones fitting the rotary processors. They also take Jobo 35mm, & 120 spirals.

I've used many ways of processing and aside from deep tanks these Jobo tanks are by far the most reliable way of developing 5x4 film. I bought my first back around 1976 and picked up a second via a wanted advert on APUG about 3 years ago. I keep one in Turkey the other here in the UK.

Ian

[Clive Gray]

or should I just give up & revert to dishes?

If you were using dish / tray processing you presumably have a darkroom? or at least suitably dark room, why not simply try using the combiplan as a dip dunk tank?

I found with E6 if you follow the instructions to the letter then the combiplan worked exactly as planned but I find it much more convenient and consistent to do dip dunk processing. Mostly now it's just the carrier I use and the tank itself is relegated to being a wash tank but there is no reason why you couldn't use a dip dunk system of agitation with a single tank.

[Joanna Carter]

I do fill the tank, but no matter how hard I tighten the top spout it still leaks if the tank is inverted.

Dennis, is there a rubber washer between the bottom of the spout and the tank? If so, you may find, as I did, that the friction of the rubber washer on the rubber top stops it sealing properly. Remove the washer and allow the rubber of the tank lid to act as the only seal. It worked for me.

[dennis]

My 'darkroom' for film loading & rare dish processing (prior to buying Combi) is a windowless loo fitted with a 'bench'/shelf. I am not sure how practical for dip & dunk. Joanna, I'll test the washerless idea with some water. Thanks again for all the suggestions. Dennis.

[numnutz]

is a windowless loo fitted with a 'bench'/shelf.

Hope you have somewhere to sit...


nn

[dennis]

numnutz,
It's the alternative one . . .
PS There are a couple of Jobo tanks on the SH Darkroom site - big one £39 & smaller £29. Reasonable or not? Dennis.