RE: Gum problem(s)

From: Tom Sobota ^lt;[email protected]>
Date: 11/18/05-12:23:15 PM Z
Message-id: <6.2.1.2.0.20051118191044.032736d8@pop3.teleline.es>

Loris,

Alcohol (or acetone) is used in other processes (i.e. carbon) to speed up
drying of the sensibilized couch so I don't think that it will react in
any way with the dichromated gum mixture. Not being a chemist
I cannot swear to this. However, experience suggests that alcohol
will evaporate rather quickly without reacting with anything.

Alcohol has a low superficial tension, so it's effects seem to be more
or less equivalent with those of a surfactant such as Photoflo. However,
alcohol will eventually disappear while the surfactant stays in the mixture.
This will, or will not, make a difference. I don't know.

Regards
Tom

At 17:52 18/11/2005, you wrote:
>Can one add pure alcohol instead of Tween or Photoflo/Ilfotol to
>facilitate coating of gum emulsion? Will alcohol get in reaction with
>dichromate and/or colloid?
>
>Regards,
>Loris.
>
>-----Original Message-----
>From: Tom Sobota [mailto:tsobota@teleline.es]
>Sent: 18 Kasım 2005 Cuma 18:14
>To: alt-photo-process-l@sask.usask.ca
>Subject: Re: Gum problem(s)
>
>...
>Photoflo is a good idea when working with dry pigments. I use Agepon,
>the Agfa equivalent, but any surfactant agent should help. Only I use it
>in minimal quantities: just a very small drop which is enough to break
>the superficial tension of the gum+dichromate mix. Perhaps you are using
>too much Photoflo?
>...
Received on Fri Nov 18 12:23:46 2005

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