U of S | Mailing List Archive | alt-photo-process-l | Re: Liquid Emulsion - Air Bubbles

Re: Liquid Emulsion - Air Bubbles

From: Ritab19106@aol.com
Subject: Liquid Emulsion - Air Bubbles
Date: Tue, 28 Nov 2006 20:31:45 -0500 (EST)

> I have consulted the Silver Emulsion bible (by Martin Reed)
> and experimented with adding a few drops of glycerin and
> also alcohol (Everclear) but neither seems to make much
> difference.

Glycerol and ethanol have little or no effect on this
matter. Tertiary butyl alcohol and bigger alcohols work
effectively as antifoaming agent. I don't use this technique
but a bit of milk can be used to suppress foaming.

There are some non-ionic surfactants that have reasonable
defoaming power. I have some of such but they are proprietary
compounds and they are very difficult to buy, unless in a
ship-load of quantity. HOWEVER, some dishwasher (machine)
rinsing agent (not detergent) is mostly a surfactant of low
foaming power, and they may have some antifoaming activity if
used in right quantity.

Silicone oil emulsions (like Kremer defoamer) are a VERY
effective defoamer but it's also easy to get defective coating
(spots of poor coating or holidays) so be very careful when
testing them. I used to use it but then phased out because of
this problem.