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  1. #1
    hal9000's Avatar
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    Combiplan vs. JOBO Expert Drum 3010

    Up until recently, I had been using a CombiPlan plastic film holder for 6 4x5" films and developing using a multi-tank array. I agitated by raising and lowering the film holder in the developer 3 times every 30 seconds. I had tested my film development more or less according to BTZS using a Stouffer step wedge and measuring the gradient at different developing times. Even though the Stouffer wedge has two fields with identical density, the results on my test negatives were always somewhat off (0.02 to 0.04 as measured on my Heiland densitometer). My curves were also somewhat uneven. I attributed this to measurement error, although I checked the densities on the Stouffer wedge several times and always got identical results.

    I got tired of developing in the dark and wanted to try the JOBO rotation system, which of course also uses less chemicals (my tank array required 1200ml to cover the film holder fully). So I splurged and bought a brand new JOBO CPP-2 with lift and a JOBO 3010 Expert Drum.

    I did a test run this weekend to check development times with the #4 speed rotation as recommended by JOBO for this drum. To my surprise, I got very smooth curves (see attachment) and the results for the duplicate density field were identical on all my test negatives.

    Looking back at some of the images I developed over the last few months, I realize that I often have visible effects which I attributed to uneven lighting due to clouds that I had not noticed when taking the picture. So now I realize that these effects and the uneven density results were due to uneven development using the CombiPlan holders. I am happy to have found that I can improve the quality of my negatives with the new system, but am also very unhappy knowing that there was uneven development with the nearly 400 4x5 sheets I have developed since I got the CombiPlan system (I used to use tray development).

    Now I need to set my new standard developer for the JOBO developing system for my normal film (FP4+). XTOL 1:1 gave me too short times with FP4+ using rotation. I aim for a gamma of 0.57 for normal development and like to have room for at least N+2 and N-1, but I am at nearly normal development with only 5 minutes. So I will either try more dilute XTOL (1:3) or another developer. I have read that at least 25ml of XTOL stock should be used per 4x5 film, so with 10 films I would need 250ml + 750ml water which is the maximum volume rated for the 3010 drum (minimum only 210ml). Or maybe I will try another developer, anyone have suggestions for rotation processing FP4? I like to have developing times of around 10-12 minutes for normal contrast so I have plenty of room on both sides.

    So for anyone else considering the CombiPlan system - I would recommend don't!
    Attached Files

  2. #2

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    The Combi-Plan was designed to be used as an inversion tank, just like you do with 35mm film in the round stainless steel tanks. This gives more vigorous agitation than your raising and lowering the film hanger in the tank. I have processed small runs of all types of film in combi-plan tanks, and have always achieved excellent results, b/w, C-41, and E-6. I always treat the tank as an inversion tank, though.

  3. #3
    hal9000's Avatar
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    I tried inversion but had problems with leaking and the lid is very hard to get on and off. So I switched to the tank array which is actually made by Nova, it consists of 5 tanks in a heated waterbath. But this requires everything to be done in the dark and of course is not designed for inversion, and obviously dunking is not enough.
    Hal

  4. #4
    Jim Noel's Avatar
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    Maybe now you will do as I did several years ago and destroy that CombiPlan so it can't ruin another workers negatives.

    I run my Expert drums even slower than "4" and haveno problem with streaks, etc.
    [FONT=Comic Sans MS]Films NOT Dead - Just getting fixed![/FONT]

  5. #5

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    Well, I don't know. If the Jobo is working well for you and you like it, then by all means use it. I'd probably do the same myself if the budget allowed for it. I have the CombiPlan tank, and use it the way it was intended - as an inversion tank. Once you develop the knack for loading it properly, it does a fine job and doesn't leak too much. Maybe the previous poster didn't tighten down the funnel enough. You loosen it to allow air to escape while pouring chemicals in and out. Tighten it down before you start inverting.

    Best of luck with the Jobo. I think you'll find that dilute XTOL will provide the elongated processing times you need.

  6. #6
    PhotoBob's Avatar
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    I have two combi-plan tanks and have no problems with either.
    One must be careful with the tightening however, as I've found out.
    On the other hand, I'd sure like a JOBO system too.
    Follow the Light John 8:12
    ~~~PhotoBob

  7. #7
    hal9000's Avatar
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    Quote Originally Posted by Jim Noel View Post
    I run my Expert drums even slower than "4" and haveno problem with streaks, etc.
    Hi Jim, what speed do you use with your Expert drum? I have only tried JOBO's recommendation (P for roll films and 4 for expert drums).
    Thanks,
    Hal

  8. #8
    Martin Reed's Avatar
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    Quote Originally Posted by hal9000 View Post
    Up until recently, I had been using a CombiPlan plastic film holder for 6 4x5" films.....
    I never got good results with the Combi using the full load of 6 sheets, and started processing 4 at a time, (with the gap between the sheets on each side) and this seemed to solve the problems. But a high level of agitation might also be an issue - I think maybe the way the film is held in curved channels tends to introduce undesirable flow characteristics and backing off on agitation should minimise this.

  9. #9

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    I also use the Combi for inversion, and once I had got te hang of it, and used it exactly as per the instructions, I have had good results with it. Looking at those curves, there is a hump in all around around density 1.6. This looks too regular, and if it was a fault due to agitation, I would have expected a more random result. If you flattened out the "bumps", then the curves look reasonable.

    One other point, the developer dilutions are not identical, so a direct comparison is perhaps not valid. I know it is probably not possible due to the amount of chemistry that can be used, but 1000ml of 1+3 will give different results to 500ml of 1+1.

    Steve

  10. #10
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    I bought one combi-plan tank, thinking of making the array for a little dip-n-dunk line in my sink if I liked it. Mine leaked from the drain plug, no matter how tight you dialed the drain stopper. After using it a few times, the lid to the tank had warped sufficiently that it could not fit on the tank properly no matter how hard you twisted and jammed. I went to the Jobo Expert drums, and have NEVER looked back. I run my Jobo CPA2 at the slowest possible setting, just above the OFF position for the motor, and I get perfectly even negatives, which print beautifully on platinum/palladium. Five Combi-Plan tanks? That's almost two Expert drums in cost! Yikes!

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