Help troubleshoot Unicolor drum film developing

[bob_mccready]

Hi everybody,

 

When I started developing 4x5 I adopted the Unicolor print drum system

after reading about people's experiences here. However, I am getting

uneven development. As you can see in the attached scan (please

forgive the low quality), I get uneven development on the two edges

that run parallel to the ribs in the drum. Since insufficient

agitation would make the edges darker, does this mean that I am

getting too much agitation, possibly due to turbulence from the ribs?

I have tried 250 ml of Rodinal at 1:25 and also 500 ml at 1:50,

hoping that the increase in volume might change the flow pattern;

there was no appreciable difference. Another peculiarity is that the

two sheets of film closer to the drum mouth develop like what you see

here, but the two sheets at the back of the drum only show a hint of

this effect. This makes me wonder if the front end cap of the drum

also increases the effect.

 

If anybody has seen this, or has any ideas I would like to hear them.

And for you Jobo fans out there, I already plan to get an Expert drum

when I can afford it.

 

thanks,

[jim_thompson1]

Jerome,

 

I have used the Unicolor drum for many years, and been very happy with it. The first thought that comes to mind when I see your example is it possible the sheets have overlapped in the drum ? I did have a similar problem when I did not have a "seperator" in there. Just a thought, like I said, I have been very happy with the system, hope you find a solution.

Good luck.

[leonard_evens]

I use a Beseler drum with a Beseler roller base, but the principle is the same. My negatives are very uniformly developed, but I use HC110 in dilution B for about 5 1/2 minutes. I've been developing the old TriX

TXT. I manage with 6 - 8 ounces of developer.

 

See my example which was scanned on my Epson 2450 and rescaled for display here.

 

You might try a different developer to see if that makes a difference. Also, are you using a motorized roller base and is it level?<div></div>

[dave_schneider]

I have used Unicolor drums, well actually cibachrome drums. Do you have dividers to keep the sheets in place? Some drums have very tall ridges to hold the print in place. I started with ciba drums which are completely smooth inside. I added small plastic ridges only about 1/8 inch tall to hold the film in place. Even then I got some signs of turbulence right at the ridges or at the ends of the ridges. The biggest factor I discovered was rotating too fast. I was rolling them by hand on a homemade roller. I discovered that I had to roll painfully slow to avoid the problem. I would also lift one end of the drum every 30 seconds to create some end to end agitation. This needs to be done gently as well to avoid problems.

 

I have all but abandoned the drums and made some individual sheet tubes instead. These seem to work much better.

[bob_mccready]

Thanks to everybody who responded.

 

I am sure the sheets did not overlap; I placed a rubber block between them that is notched to grip the V-shaped pair of ribs. I use a manual roller base rather than motorized, but I did check with a level before beginning. I think I will try Dave's advice and try rolling very slow; that might help if in fact it is overagitation.

[matthew_brain]

Are you using constant agitation or intermittent. The unidrums are designed for a roller base that is always going. If you are letting the drum sit at any point, the developer may be blocking below the rims.

 

Another option - have you made sure that the emulsion is facing toward the center of the drum? the way it sits, only the shorter edge of the filmbase should be in contact with the drum. If you had the emulsion facing outward by mistake then the shorter edges of the film but not get much development (as you have).

 

Like many others, I have no trouble with the unidrum on its base

 

Let us know how you go.

 

Matt

[sjmurray]

I had similar uneven development along the edges where the large ribs are in the Unidrum, which I presume is from turbulance created by the ribs. I tried the motorized base as well as gentler hand rolling to no avail. As a result, I darkened my basement at night and develop in trays like I did in the old days. Now my negs come out perfect and I can do up to about 8 at a time. I have an 8x10 Unidrum and two motorized bases I will sell.

[steve_feldman2]

Jerome,

 

As others have commented, I too have had no problems using the Uniroller drum and motor base. I bought a second base recently for $8 just as a back-up if my old one ever fails. Your undeveloped edge looks suspiciously like an over-lap. I use a small cut down plastic spring clip as shown on another photo site link regarding the drum and base system. It works. But it is a bit tricky in total darkness and by feel only.

 

Here's an idea. Develop one neg on each side of the "V" emulsion towards the center and check for even or uneven results. Then try four with your spacer. Before removing each neg look inside the drum for the final positions of each of the negs. Then carefully extract each neg, one at a time and see what happens. I'd like to see the "rubber block" you mention. Can you post?

[paul_frank]

I too, use rodinal and the unicolor system. I process apx 100, 4 sheets at a time, in 250ml of rodinal 1:50 for 14 min and have never seen this happen to any of my negatives. Early on I had overlap problems, and this does not really look like that to me. I don't really see how it could be overlapping, unless everyone else loads their film in there differently from me; When I had overlap issues there were problems on the long side of the neg, not the short side.

 

You don't say what film and what developing time. have you tried longer developing times? it seems to me that since density is not building up on the edges that maybe they need more development.

[john_hicks___]

That's rather extreme; I haven't seen such unevenness. I didn't see a mention, but if you use any sort of prerinse or presoak, stop doing that.

[tim_atherton2]

I haven't used your developer combination, but have had good results for 4x5 with this setup.

 

But, I would suggest the motorized roller base rather than your hand rolling - they are usually cheap. Also, once you have that, with it's regular and continuous agitation, you also have the option of introducing "irregulatirites" into the devloping movement something I found I need for 8x10 film, but not 4x5 (and very easy to do). Though my guess is that the rgeular and continuous acxtion may solve your problem.

 

If you're using the little rubber doohiky that comes with the drums to stop overlap, that should work (though I've still managed to overlap them once, even with it...)

 

 

tim

[__jon__]

>That's rather extreme; I haven't seen such unevenness. I didn't

see a mention, but if you use any sort of prerinse or presoak,

stop doing that.

 

5 min. presoak here--absolutely no uneveness. Hp5, HC110, Dil.

B.

 

Get the motorized base, it works great.

[bob_mccready]

I don't know if anybody is still following this thread, but I thought I would relate my learning experiences.

 

After reading everyone's comments, I decided to try the ancient Cibachrome motor base I had. The base doesn't keep a very uniform speed, but it made it through this batch. It is also not self-reversing, so I picked the drum up and turned it so it was facing the other way every 60 seconds. This batch of film turned out very well, evenly developed.

 

Based on this result, I decided to see if the original problem had been caused by insufficient agitation. I went back to the manual roller base and developed a batch of film using significantly higher RPMs (I would guess about 50-60 rpm). This batch of film also turned out nice.

 

So it seems the problem was probably due to insufficient agitation.

 

thanks for everybody's help,