From: Richard Knoppow (dickburk@ix.netcom.com)
Date: 02/03/01-04:56:34 PM Z
At 04:10 PM 02/03/2001 +0000, you wrote:
>Richard Knoppow wrote:
>
>> I use Unidrums and a Bessler drum for large format negatives. I have a
>> reversing Unidrum roller. They do a good job but I discovered I was getting
>> bromide streaks at very dense highlights on either side in the direction or
>> rotation. Evidently there is not enough turbulence to move the developer
>> sideways, so the reaction products keep being swept back and forth along
>> the same path. The cure is to agitate the drum sideways occasionally, or to
>> roll it manually with some irregularity. My largest negatives are 8x10 but
>> I've frequently done four at a time in the 16x20 drum.
>
>Richard,
>
>I have a Kindermann tank agitator, like a Beseler or Unidrum roller,
except it
>has one end blocked by the motor housing which makes a long tube
impossible to
>use. Anyway, it rolls and tilts (lifts) the tank (drum) by means of an
>elliptically shaped gear. Could you tape or somehow secure a small "nodule"
>onto the rollers of your Unidrum, which would then tilt or lift your tube
up at
>regular intervals? A modification of a round roller gear into something
>elliptical would seem the easy solution, it would have to be easier than
>manually agitating every time you develop film.
>
>Just thinking out loud.
>--
>Darryl Baird
>
I might be able to rig something but would have to figure out a way of
keeping the drum on the roller, or at least on the eccentrics, since I
suspect it would tend to work its way off.
Judy said something about laminar flow along the surface, and I think
this is exactly the problem here, along with a stong directional effect.
Directional effects of this sort used to plague motion picture developing
machines before spray type development was adopted.
---- Richard Knoppow Los Angeles,Ca. dickburk@ix.netcom.com
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