film development in JOBO multitank : LUSENET : Large format photography : One Thread

Hi Folks, I have a JOBO Multitank 5/2551. It holds to reels of 4*5. Can any one tell me how much developer to put in this thing. I plan on floating it in a tub of water and spinning it by hand. Is there difference in the amount of fluid if I only do one reel of negs? It does have a matrix on the side: 4*5, 8, 560 ml, under 2509. I have no clue as to what that means. Thanks in advance. Also, for this type of development do you knock time off development; I mean, I assume this is constant development. Thanks, David

-- david clark (, March 14, 2000


The Jobo system comes in two varieties, tanks for film, and drums for prints. I think it's only the print drums that are meant to be agitated by spinning, the tanks are more suited to inversion agitation. I've got a load of info on the Jobo system stashed away somewhere, I'll look it out if I can find it.

I bought a Jobo system specifically for 5"x4" processing and was really disappointed with the results. Apart from the fiddly loading, it gave uneven development and foaming marks if all the film-slots were filled. I now use a small sealable stainless-steel deep tank with individual film holders.

-- Pete Andrews (, March 14, 2000.

Your tank will hold 12 4x5 negs and use 560ml. of fluids to develop the film

I recommend you rotate the tank slowly while floating, I use the jobo system the tanks rotate slowly

-- William Jefferson (, March 14, 2000.

See this page:

-- William Marderness (, March 14, 2000.

See this page: http://www.jobo- Specifications

-- William Marderness (, March 14, 2000.

I have no experience with the tank you are using but I use Jobo all the time both with tanks for roll film and expert drums for large format. The expert drums are highly recommended for sheets, surpassing quality of the 4x5 reel/tank system by far. But your tank can very easily be rolls in a tub, contrary to the first post. Rotary processing is an extremely even, accurate way of processing but frought with procedural problems like with any method. Once you get your hand rotation down it should work beautifully. I have an ATL 2 and it contributes speed, evenness, accuracy and chemical tempering, but not much else if your hand rotation skill are honed. For me there isn't a better way to process. I use BTZS tubes for really big stuff and on the road, but always come home to my Jobo happily.

As for amounts, the other posts were right on and I can't add to it. For sheet film, if you can gauge it somehow, rotation is best at about 75rpm. Roll film, in Jobo, is done at a higher rate...100 rpm.

-- Rob Tucher (, March 17, 2000.

I use the Jobo system with inversion agitation for B&W work. Rotary processing isn't particularly recommended for B&W because of potential streaking. A lot of things, such as developer, can influence wheter or not rotary works well with B& W, so I just avoid the problem by not using rotaty processing.

With inversion agitation, I never get any streaking. I load only the bottom reel, and use the top to keep the lower one down. (I'm going to cut a piece of plastic pipe to do this when I get around to it.)

An article in one of the good darkroom magazines, a few years back, indicated the success of using stainless tanks for roll film, with twice as much tank height as the film took up, and just enough developer to cover the reels. During inversion, all the developer moves to the top, allowing full intermixing of depleted and fresh developer, and full flow past the reels and film edges. My approach with the Jobo duplicates this effect. I've never had any agitation problems as a result.

I measured 1.4 liters as the minimum to completely cover the lower reel, so that is what I use. Since this is a lot of liquid I've tried two approaches: very dilute developer one-shot developers and reusing full strength developers. The second approach really requires replenishment or adjusting times for the number of films previously processed. The first approach is easier and more likely to give consistent results, so I recommend it. Try Xtol at 1:3. Kodak publishes times for this dilution. You could use other highly diluted developers but you'll have to test for the proper time.

If you try the rotary process:

1. Make sure you use enough developer concentrate for the film area you are processing. You can breakdown the capacity. For example, if it says 1 quart will process 10 8x10 sheets. for 6 sheets of 4x5 you need 32 ounces divided by 10 (to get ounces per 8x10 sheet) multiplied 1.5 (6 sheets of 4x5 = 1.5 sheets of 8x10) or 4.8 ounces of the stock as a minimum. You need to do this calculation as well if you are doing inversion processing.

2. Make sure the developer (straight or diluted) covers the film when the tank is horizontal. This is probably the volume indicated on the tank, and it doesn't matter if you use one or 2 reels, since the volume of the film itself is inconsequential. You're just trying to cover all the film with the developer puddle.

Best of luck, Charlie

-- Charlie Strack (, March 21, 2000.

Moderation questions? read the FAQ