Archived posting to the Leica Users Group, 1999/02/18

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Subject: [Leica] RE: Photoflo and plastic reels
From: Jim Brick <jimbrick@photoaccess.com>
Date: Thu, 18 Feb 1999 16:06:59 -0800

Could very well be. But if you beat it around too much, it foams-up like
detergent or soap. I know that a single drop of "clear" Ivory liquid
(detergent I suppose), to a couple of liters of water, can be used in an
emergency. So photoflo, to me, acts "soapy". Even if it isn't.

thanks Alexey,

Jim

At 03:46 PM 2/18/99 +0000, you wrote:
>Jim Brick wrote:
>
>> Photoflo works because it is a soapy solution with a pH above 7.
>
>So far as I can tell Photoflo is simply nonionic detergent - NP40 or
>Triton X-100 or Tween20. It works by decreasing the wash water's 
>surface tension, reducing droplet formation on the film surface.
>
>If I'm correct about this, Photoflo is neither soapy (soaps are IONIC
>detergents), nor does it affect pH. If it did change pH it would do so 
>by containing a buffer, and this would, I think, tend to INCREASE 
>spotting because buffers generally are salts.
>
>For several years I've used NP40 instead of Photoflo (I use an outdated 
>lab stock that I no longer trust for my biochemical work). Seems to work
>perfectly.
>..........................................................................
>Alexey Merz | URL: http://www.webcom.com/alexey | email: alexey@webcom.com
>            | PGP public key: http://pgp5.ai.mit.edu/ | voice:503/494-6840
>