Developer with Jobo

[stefano_4565]

After developing with Jobo 2521 my 4 x5 films I see a line to the center on the long side (density difference). who can help me?
thanks
Stefano (Italy)

[Richard Littlewood]

Stefano
I had edge density problems with the 5x4 spirals too, some sheets worse than others depending on the slot of the spiral. What I did was first get a sharp scalpel type knife and trim the moulded 'pips' around the spiral edges into more of a wedge shape, so they still do their job without contacting the film surface - this bit is quite easy! The fiddly bit- I glued (epoxy resin) little plastic pieces not much bigger than a pin head around the spiral edges - about 3 per side, with the intention of keeping the film surface away from the spiral edge. This was a dog of a task, but having the emulsion not touching the spiral is the answer. Just load a dry sheet into the spiral and see where it touches - this is the cause, and the problem area, and it differs on each slot.

My negs now are incredibly evenly developed with no trace of edge effects whatsoever, and if you have the time etc I'd give it a shot. The only upshot of these glued on 'pips' is it makes loading the sheets a little more difficult, but a smooth, round shaped pip helps. I always load the spirals without the Jobo loader anyway, so I'm used to it.

I've messed around 'improving' all sorts of photo gear, but this is one I'm really glad I did!
All the best.

[Ted Harris]

The expert series drums are an even better solution.

[ronald moravec]

Uneven density is the result of agitation that is insufficient to replenish the developer across the entire film surface. In this case, the edges are getting more than the center. With roll film, this can be the result of twisting the reel and not lifting it up and down at the same time.

The Jobo makes this work because film is rotated on a horizontal axis and the film is removed and replaced in the liquid. If you are doing manual agitation, invert twice in 10 sec once per minute. This gives the developer time to flow into the free space in the top and return. Twist 1/4 turn upon setting down.

Jobo has two versions of the 4x5 reel. The newer one has baffles that are removed when the film is removed and they serve to hold the sheets in place and distribute the liquids more efficiently. I do not believe they are necessary if you do hand processing except for holding the film in place.

I think I read somewhere they now recomment only using 4 sheets, not 6, in their reels.

[Richard Littlewood]

Interesting. I've not found the baffles influence the development, even using 6 sheets per spiral. A couple of times I've done 12 in one spiral, back to back, but I'm older now. Another thing I've found helps is using a greater volume of dev solution. For 12 sheets I'm using 900ml of ID-11, at 1+2 dilution. I think Jobo reccomend something like 650ml to do the same. This will do for stop and fix, but perhaps more when it comes to dev is not a bad thing.

[Nick_3536]

The volume Jobo mentions is the least amount that will cover the film. It's a floor not really a reccomended level. Use no less.

If I understand the orginal question he is getting problems in the middle of the sheet?

[Richard Littlewood]

Having used these spiral types quite a lot, I've never had problems in the centre of a sheet, but until I mucked around with them I always had problems down the long edges.

[Joseph O'Neil]

I use a 2551 Jobo drum, on a unicolour roller base. I have also used this same drum on a manual roller base before too. I used to have your problem, and here's what I did that seemed to solve the problem.

1) As stated above, use a larger volume solution that indicated. For example, I do two - 4x5 reels at once. Minimum reccomended solution is 600ml (I think) - I use 700ml.

2) Do not load up the reels to maximum. For example, each of my Jobo reels takes a total of 6 sheets of film. I never go above 4 sheets per reel - I use the outer and inner slots, and leave the middle slot empty always. I dunno why - maybe it's just physically not large enough to allow proper flowing of liquids - but whatever the reason, I never seem to get good results loading up 6 sheets per reel, regardless of film type or developer used. 4 sheets per reel - works great.

3) water pre-soak. I always do this. You will find a great deal of debate over the usefullness of a water presoak, but for me, it works - at least the way I ahve things setup. However, I do not just fill up the druma nd let it sit, I fill up the drum then put it on the roller base and let it run 3-4 minutes, then dump, and introduce my developer. Your milage will vary.

Anyhow, water pre-soak, increased volumne of solution used and 4 sheets per reel, not 6, solved the problem for me. Maybe I needed to do only one of those things, so try and see for yourself.
joe

[Richard Littlewood]

I agree with Joe also, a pre-soak for about 3 mins will do no harm at all.

[stefano_4565]

Thanks for your advices. But I do not understand the line in the perpendicular means (different density) to the rotation board. And possible put the scanning of the negative one in the forum to let you see it?

[Richard Littlewood]

Stefano. Post a neg and let's have a look.

[stefano_4565]

http://www.pbase.com/phste/image/45860304/original
My problem ..........
tanks

[Richard Littlewood]

Looks a bit like chemical streaking. How do you process the negs? Developer times/type etc, etc.

[Paul Butzi]

Were the reels and tanks completely dry when you loaded the tank and started the process? I've seen weird stuff like this on my film (in a Jobo 3010, no less) that I eventually tracked down to my being lazy and not drying the lid of the drum thoroughly - a drop of water would fall off and wet the film, and the difference between wet and dry would leave a mark.

I have no idea if that's the problem, but it's an easy thing to fix, so I thought I'd mention it.

[stefano_4565]

The film is Efke 25 iso and developer pyro (6 min) 20°C, agitation to hand.
The drum was dry.
Thanks

[Nick_3536]

Did you roll the tank or invert it? How much developer did you use?

Does the problem extend all the way across the negative? Or is it just the area you circled?

If it's just the area you circled I wonder if it could be a film defect. Didn't Efke have a bad batch last year?

[stefano_4565]

The tank I make it roll, inside this I put us 500 ml. The films are very fresh

[paulr]

I've been using the jobo 4x5 reels (not the expert drums) for over ten years with good results, processing 12 negs at a time on two reels. It's true that a good presoak helps. It's also important that the rotation speed of your motor base is within a certain range, and that it reverses at least once every 5 seconds, to prevent laminar flow patterns from forming. Jobo technical support is excellent, and they can give more specifific advice.

Another factor is the developer you use. Some developers exagerate unevenness due to flow differences more than others. In general, weak developers or ones that produces a lot of development-restraining oxidation products are likely to give less even results. If you're using a super-compensating developer or one that's known for producing mackie lines, then this almost certainly makes things worse. Personally, with D-76 I got an annoying amount of edge density buildup. With the glycin-hydroquinone-phenidone formula I use now there's hardly any.

I haven't used the expert drums, but supposedly they solve all evenness problems by their design.

[Dan Jolicoeur]

I had a similar problem once with a few loads to finally figure out that I had left out the center spindle. I have to blame that one on the spouse for moving my stuff. She thought it was part of the paint roller I was using to paint the house with last winter.