Uneven Development with Tri-X in Jobo

[andrew_herrick1]

Hi all,

 

Although the issue of uneven development has been addressed in a

number of posts in the archives, I would appreciate any insights

people can provide on my problem.

 

I am developing Tri-X in a Jobo drum connected to a Jobo CPE-2. I am

developing in D-76 1+1 at 20C/68F, using 300ml of solution, on the

slow rotation speed.

 

I am getting uneven development along the edges, and it's driving me

nuts. I have previously not been using a pre-soak, so tonight I tried

it to see if it would help; I tried a 3 minute pre-soak but it hasn't

helped. (I know there are varying views as to whether you need a pre-

soak, but I figured that with an older emulsion like this, it might

be significant. Unfortunately it didn't help. Should I increase to 5

minutes?)

 

Does anyone have experience with this, and if so what did they do?

 

(As an aside, when I got the drum it came with two separate black

plastic flaps. I never knew what they did and have never used them.

Confronted with this problem I dug them out tonight and see now that

they fit in the spool. It occurs to me they may be designed to smooth

out the flow of chemicals over the film surface and hence fix my

problem. I will try this next, but does anyone know what these are

for?)

 

Thanks so much for any advice.

 

Andrew Herrick

[robert_krapfl]

I don't think I can help you with the uneven development. But, the little rubber things that come with the Jobo reels are for dividing two rolls of 120 film on the same reel.

[tom_perkins]

Andrew--

I assume it is the 2500 series drum, and I had the same problem with Delta 400 before they quit making it. The flaps are to keep the sheets on the reel. The instructions also say to develop no more than 5 sheets, even though the reel takes six. I finally switched to a 3006 drum, pricey but even to the edges. Try the 5 minute pre-soak and more solution. Good luck. Tom Perkins

[jose_angel]

I don't experienced uneven development with 2500 and CPA-2. I always use the drum with one to six sheets, emulsion side pointing to the axis of the reel, and always with the two plastic flaps in the correct position. Always 270ml. of solution. If you use the system as I do, I think there isn't a "mechanical" problem.

 

With the last films I started using pre-soak (5 minutes), and I don't experienced a diference in the results, but my dev-film combination is different.

 

Hope this helps,

[skygzr]

Hi Andrew -

 

The drum speed makes a big difference, in my experience. I had all kinds of streaks and mottling at slower speeds. In fact, the newer JOBO units only have the higher setting (about 80RPM). I use the faster speed and the plastic "wings", and have no trouble.

[henry_a]

Try using 600ml of solution instead of 300ml - twice as much developer as you are using now - I think it will solve your problem. Jobo suggests that you use a minimal amount of developer, but it may not be the best amount. The CPE2 will just turn 600ml or so. The larger models can handle more liquid, but 600ml will solve your problem. Use the flaps, they keep the film in the slots. Do you have the lift? That helps a lot in getting the fluids in and out and gives even development. You will get some increase in development at the edges with this drum. but it should be even.

[jerry_breault]

Andrew,

 

There were development problems with the early sheet film reels, 2509. The new reels, 2509n had some features added that eliminate those early problems, I use 2509n reels in the 2523 and 2553 tanks for anywhere from 2 to 12 sheets on a CPE-2 Plus. I use TMY and D23 and I experience no streaking or uneven development. The CPE-2 Plus does have 1 speed only, and it is about 75 RPM. The flaps must be used at all times to get predictable results.

 

Jerry Breault

[neal_shields]

I had the same problem with Tmax and several people on this site said "use more developer". I did and the problem went away.

 

I "over expose" by one stop, and I think that denser negatives make the problem more likely.

 

Neal