From: Richard Knoppow (dickburk@ix.netcom.com)
Date: 02/02/01-07:22:23 PM Z
At 11:37 PM 02/01/2001 -0400, you wrote:
>Hi Ellen,
>
>The ABS plastic tubes work fine for 4X5 up to 8X10 negatives (1 1/2" - 3"
>ID tubing) but I would not recommend it for 16X20 negatives. For one thing
>I am not even sure you can get ABS tubing large enough for a 16X20. The
>largest size I have seen is 4" ID. That fits in one 12X20, barely. However,
>there is another problem with the larege sizes;the cap is so big you can
>not easily snap it on and off as you can with the smaller sizes. The result
>is that you have to use one of the screw-on end caps and that makes it very
>difficult to pour in and discard rapidly the chemistry.
>
>Best bet for you in my opinion is to buy one of the 16X20 Unidrum or
>Beseler (or perhaps there are others) print drums. I see them all the time
>dirt cheap on ebay, and used motor bases also appear frequently at good
>prices. The motor bases are of two types:one type reverses direction, while
>the other type always goes in one direction. I use the former type and
>don't know how the second might work.
>
>Sandy King
Long thread snipped...
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 Knoppow Los Angeles,Ca. dickburk@ix.netcom.com
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