Combi Plan dev tank teething problems

[Baxter Bradford]

I've just bought an HP Combi-plan T' tank to replace a stainless Nikor spiral tank which was scratching the 4x5 negs with occasional other problems.

I need to use inversion and have to use it in daylight mode, since I do not have a proper darkroom. I am only using it for B+W and currently am using DiXactol developer with Agfa APX100 film.

I have found a number of problems on first use, which hopefully experienced users will be able to offer advice, dodges or techniques to alleviate. Research led me to believe that the Combi--tank is the preferred dev tank for 4x5 and so either these problems are not significant, or more likely, I'm missing a few tricks and need more procatise!

1. Whilst loading film and placing film retaining clip on, I managed to get two sheets in one of the vee's preventing process fluids reaching top portion of one sheet. Also managed to get two sheets in one slot, despite trying to be careful and using fingers to locate sheet along loading guide.

2. Top valve is very stiff to rotate especially with wet fingers. If not closed fully, dev etc leaks out of vent.

3. It takes an inordinate amount of time to pour fluid in, 30 s or so I think. Clearly there is risk of uneven development and stop washes not being so effective. By applying breath pressure to funnel I was able to speed up drain process, but clearly have reservations about doing this on regular basis!

4. After the fix am I right that I can lift off lid to speed up wash water changes? If so, can I also do this for the staining stage of DiXactol developer?

Additional query, have just processed a 120 roll of APX400 which seems to have a much greater base fog. Or have I messed up on this too?!!!

[fw]

I also use a Combi tank - looking at your questions ;

1. You do need to practice loading film to avoid such problems. Doing this in daylight with a few spare sheets will help you get it right in the dark.

2. First, you should probably be wearing gloves, especially if you are using a developer such as DiXactol, which uses similar chemistry to pyrogallol, and which can be absorbed through the skin with potentially harmful results. The stiff valve may just need a bit of time to loosen up, but as this on a large thread you may have a poorly made part which you may be able to return to the manufacturer for a replacement.

3. Breath pressure - !!! Please see above comments on safety using photographic chemicals. By doing this kind of thing, you run the risk of burning the sensitive skin in your mouth, poisoning yourself, and increasing the chances of splashing chemicals into your eyes.

In order to get the tank to drain efficiently, you need to loosen the top valve to allow air to replace the draining liquid. The tank should drain in 20 - 30 seconds.

4. You can remove the lid about halfway through the fix process, and keep it off thereafter. The post fix staining process can be done in daylight, as can the film wash.

[paul owen]

Persevere! There is a definite knack to loading the carrier - practice in daylight helps, but just take your time when loading. This may help though!! Here i the UK we have "Blu Tak" which is a putty-like material designed for holding posters to walls, etc. If you have a similar product then try "fixing" the carrier to the worksurface with a "blob" - you then have 2 hands free to guide the sheets in. I agree about the stifness of the top valve - took the skin off my fingers!! But it does loosen with use, and wearing gloves helps, so does a cloth. Filling the tank is also worrying - it takes such a long time, but I have found that by twisting the valve just past the tip of the arrow symbol on the lid allows the liquid to enter faster, also slightly tilting the tank whilst filling seems to speed things up. despite these drawbacks. I haven't found any signs of uneven development. Another trick is to lower the clip that holds the film in the carrier just enough the lock the sheets in, too far and the film pops out, too little and it escapes!! THIS IS WORTH PRACTICING IN DAYLIGHT, COUNT THE CLICKS (AS THE CLIP LOWERS) AND THIS HELPS WHEN LOADING IN THE DARK!!!! Oh yes, when inverting the tank do it gently and slowly, like you would do with 120/35mm but in slow motion, stops the film escaping!!! Sounds like a lot of hassle, but it does all fall into place and it is a good system for 5x4. Good luck Paul

[Dave_958]

I eliminated this recurring problem of two negatives ending up in the same slot by using the slotted separator and clipping it into place after all of the negatives have been inserted. Without the separator and clip, agitation tends to dislodge the negatives resulting in the problem you encountered. To speed up outflow, I do just what Baxter describes. When he refers to loosening the threaded cap on the funnel on the upended tank, he means only part way, so that no light leakage occurs............................................

[David E. Rose]

Having two tanks eliminates the fill/drain time- this may not work for you if you can't achieve darkness during the process. At the start, I have the film loaded in one tank with the lid on, the other tank filled with developer and without the lid. When I am ready to start development, I turn off the lights and remove the film rack from the enclosed dry tank and place it in the developer tank while starting the timer. The lid goes on, then the room lights. About 15sec. before the end of development, the lights go off, I remove the film rack, and as the timer sounds, I place the rack into the original holding tank (which has been filled with stop bath). After the stop is complete, I use the normal fill/drain method for the fix as the timing is not as critical. I wash the film in the tank with no lid, water going in the top and out the bottom.

As for film loading errors, experience will cure these. Practice with old film in the light will help. It is very important to carefully check by feel that you have the films in their slots and not touching each other. It is best if you can limit yourself to 4 sheets at a time- more space between sheets.

Have faith, the Combi-plan has given me great negatives for years- even before I developed my two tank approach.

[Jeff Scott]

I eliminated the problems you are experiencing when I chucked the tank and bought a Jobo 2500 Series tank and reel that can be inversion processed. There were too many problems with the HP tank including everything you mentioned, especially uneven development. Try processing a sheet of film that was exposed to a evenly lit gray seamless and see how the mottled appearance can ruin skys and other even areas in your image.

[Daniel luu Van Lang]

Hi, I also use the combi tank for a few weeks, I also have the same problems. Despite I'm loading the films very carefully, I already had two sheets in the same slot at the end of the process. I think we have to screw the system very tight until there is no bit of play on it, and we must process carefully by turning it over slowly. I use a piece of rag to rotate the top valve. I start to pour the fluid 30 sec before the end of the theoretic processing time, it takes 30sec more to fill the tank with the next fluid, but it doesn't matter in my experience. You see, I have no miraculous solution to give but if anybody got it, I will appreciate too! Regards

[neil poulsen]

I had one of these and got rid of it for similar reasons. Plus, I got surge marks around the top piece that keeps the film in the slots. Perhaps this last problem could have been solved through different agitation and making sure the tank was full. Anyway, I got rid of it.

[Jorge Gasteazoro]

I agree with Jeffrey and Neil, get a Jobo drum either the 2500 series or the expert drums, a Beseler or unicolor base and you are good to go...

[Baxter Bradford]

Thanks very much for the advice. I shall practise doing it with the lights on, get my blu-tack out and then when the lights go out.....wahaay!

Glad that it seems I'm not the only one to have experienced difficultirs and yes I too lost skin turning the valve!

Bax