[pure-silver] Re: Weird Film Issue - Part II
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Thu, 10 May 2012 10:55:24 -0700
----- Original Message -----
From: "Nicholas O. Lindan" <nolindan@xxxxxxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Thursday, May 10, 2012 10:24 AM
Subject: [pure-silver] Re: Weird Film Issue - Part II
Photoflo 600 is the 'industrial' version. It has 3x the
concentration of Triton and uses ethylene glycol rather
than propylene. It will suds-up just like PF200.
If there were to be an anti-foaming agent I'd lay odds it
would be good ole' Dimethylpolysiloxane.
I add PF directly to a bottle of isopropyl alcohol. 13ml
of PF600 to a quart of 70% isopropyl gives a stock that
gets diluted 1:7 for use (1oz per 35mm film reel).
Nicholas O. Lindan
Cleveland Engineering Design, LLC
Cleveland, Ohio 44121
A little research shows that there is a considerable
difference in the toxicity of propylene and ethylene glycol.
Propylene glycol is relatively non-toxic and is used in food
and cosmetic products. That may be why Kodak chose it for a
product aimed mostly at home darkrooms. Ethylene glycol is
moderately toxic, one article points out that is danger is
from its sweet taste which may lead children to ingest it.
Both are used as anti-freeze and as wetting agents and
humectants. I don't know how to tell the relative
effectiveness. Kodak chose the ethylene for the industrial
form of Photo-Flo but the reason is obscure to me. Perhaps
cost or effectiveness. Someone with more chemical knowledge
than I can perhaps explain. The other ingredient of both
kinds of Photo-Flo appears to be Triton-X 100, AKA a bunch
of chemical names, a non-ionic surfactant. There are also
several other products sold under the Triton-X name, see:
http://www.dow.com/surfactants/products/octyl.htm
--
Richard Knoppow
Los Angeles
WB6KBL
dickburk@xxxxxxxxxxxxx
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