Archived posting to the Leica Users Group, 2009/04/21

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Subject: [Leica] LUG Digest, Vol 41, Issue 199
From: lrzeitlin at optonline.net (Lawrence Zeitlin)
Date: Wed, 22 Apr 2009 00:42:30 -0400
References: <mailman.164.1240340697.926.lug@leica-users.org>

On Apr 21, 2009, at 3:04 PM, Jim wrote:

> First, it is filled with dust spots, even though my basement is  
> clean.  Any
> thoughts on how to avoid this?  I hung the film to dry from a ceiling
> rafter, with clips at top and bottom.
> Second, I had streaks across the film, even after a five-minute  
> wash cycle
> with photoflo.


Jim,

A basement that looks clean to the naked eye might as well be a sandy  
beach to wet film. Illuminate the basement with a concentrated  
flashlight beam or the projection beam from a slide projector to see  
the millions of dust specks floating around. The best way to avoid  
spots on film is to dry it in an enclosed space or cabinet with  
filtered air. In over 60 years of photography the absolute best film  
dryer I've ever found was the Kleen-Dri, a device made by Statham  
Instruments, Inc. Statham Instruments made professional measurement  
instruments for a number of years and is well known in the  
electronics industry. The dryer consists of a plastic tube big enough  
to hold a stack of four Nikkor wire film reels. Near the base of the  
tube is a metal container filled with silica gel, a powerful  
desiccant. Below the desiccant container is a small fan. The cover of  
the film tube contains a foam filter. The whole thing  is about 18  
inches tall and 6 inches wide and fits into a small cabinet.

In operation the reels of film are simply immersed in a very dilute  
Photo Flo solution, shaken a few times to rid them of large water  
drops, then placed into the drying tube. The film is not removed from  
the reels or touched by the fingers. The tube is covered and the fan  
plugged in. The fan draws air through the reels, through the  
desiccant cartridge where the water is absorbed, recirculated outside  
the film reels to the cover where any dust particles are captured by  
the foam and then through the film, et cetera. Drying take place in  
30 minutes or less. After drying the equivalent of 20 reels of 36  
exposures the drying time will increase. When the time increases to  
40 minutes or so, the desiccant cartridge is refreshed by heating in  
a 450 degree oven for two hours.

I don't know if the Kleen-Dri is still being made. Mine is now 30  
years old and still functions perfectly. What is there to go wrong? E- 
Bay might have one or you might find in a clearance sale from an old  
photo store. If you are the least bit handy with tools, a similar  
device might be cobbled up out of a length of PVC plumbing drain  
pipe. It ain't brain surgery.

Larry Z