jobo problems

[Ugo]

Hi All,

I develop 6 4x5 sheets with the Jobo 2521 tank and the 2509n reel by hand inversion.
I frequently see marks at the corners of the most external sheets. They appear like the ones you can see in attached Fig1 and in Fig2 (arrows). They seem to me the marks left by the little pin holders. How can I get rid of them?

This is a summary of my development procedure

-4' water presoak, 1' agitation and then 15'' agitation every minute

-7' HC110 1:12, 1' agitation and then 15'' agitation every minute
-30'' water wash, continuous agitation

-4' Fix, 30'' agitation and then 5'' agitation every 30''
-30'' water wash, continuous agitation

-2' Hypoclearing, 30'' agitation and then 5'' agitation every 30''
-5' wash under a water flush

solutions volume 1400 ml

I will be very grateful to you if you could help me. Thanks

[paulr]

These are probably streaks from uneven developer flow over the reels during agitation. The reels aren't designed to provide smooth flow in that direction. The reels are carefully designed for smooth flow while rotating in a processor or motor base. This is what a job technician told me when I asked about hand agitation.

Some film/developer combinations will probably reduce streaking; some will probably make it worse.

[Ron Marshall]

This is an option, if you want to hand roll but cannot get what you want from your current Jobo. I hand-roll the Jobo 3010 and get fine results.

[ronald moravec]

Done inversion many times without a problem using same set up. Make sure emulsion is facing inward. Use the wing or baffles that attach to the reel that hold the sheets in place. Invert two times and rotate 90 degrees upon setting down.

There is no such thing as flow marks, only insufficient agitation over the rest of the area so the developer is not replenished there.

1400 cc is too much developer. Fill the tank with water and add the reel. Water will not cover completely the reel as the tank is not deep enough. Use 100 cc more.

I used 1400 when I developed with PMK and wanted almost no air space to oxidise the developer. For none-pyro you want only to cover the reel. You want all the extra space in the top so the developer has a place to go thus maximising the flow across the film. With the PMK ,I did agitation every 15 sec so it worked. With HC110, one agitation of two inversions per minute is sufficient, although two inversions per 30 sec is ok.

It is best is you add the reel to an already full tank in the dark, add the cap and last 100 cc, then do initial inversions. You have to do this fast to not mark the film.

1:12 is pretty concentrated HC110, unless you mean from a stock made from a concentrate. Normally it is mixed from the syrup 1:32. Unless you live in Europe and this does not apply as theirs is different.

Lastly I must say I can`t see the example. All that is there is a red X.

[Richard Littlewood]

There is a really good thread on APUG about this right now.

[Denis Pleic]

"There is a really good thread on APUG about this right now.

--Richard Littlewood"

Yep, thread started by yours truly. I got the same problem (plus streaks along the longer edges of the negative) - you can see my scanned examples in that thread - only I used JOBO CPE (older) processor.

One possible solution proposed there is to use higher speed on JOBO (I used the slower speed) to avoid this, and another is to try to modify the reel itself...

I'll try higher rotation speed next time.

BTW, previously I developed a couple of negs without the reel in 2523 tank on JOBO processor - as described here:
http://www.apug.org/forums/showthread.php?t=19737&page=2&pp=10

The negs came out perfect!

If you can't get rid of those marks using the reel, you might try that... the downside being that you can only develop 2 negs at a time.

Denis

[ronald moravec]

The computer at work shows the marks. I have never seen anything like them following the procedure I outlined above.

The pins that hold the wings to my reel are only 1/32" or .010" long.

The bottom shows some form of mottling or a scanning artifact. If it is in the neg which you may check with a loupe, it is a sure sign of ineffective agitation.

[Mike Butler]

I've been having this problem, too, and I'm going to give Ronald's plan a try.

One thing I've also noticed is that the marks seem to be worse on the innermost 2 negatives, so I've gone to loading four negatives on the reel. That helps a bit.

[Richard Littlewood]

The 2509n reels do seem to produce better negs via inversion than they do using rotary processing with a Jobo. Perhaps a way round the edge effects might be to use inversion for the developing stage, then whack the drum onto the Jobo processor for stop and fix and washes!