RE: temperaprint & foaming

Hi Gord,

You did roll to a piece of tile or glass (until the roller was about "dry")
before rolling to the paper, right? That is, we are not talking about very
wet rolling. It is almost like rolling the ink for printmaking. The ink is
not running wet.

I did that and didn't remember having much problem with bubbles.

Dave

-----Original Message-----
From: Gordon J. Holtslander [mailto:holtsg@duke.usask.ca]
Sent: Monday, February 13, 2006 1:16 PM
To: alt-photo-process-l@usask.ca
Subject: temperaprint & foaming

Hi:

I continue to fiddle with tempera printing - still not happy with coating.

I've tried using a brush, roller, and paint pads - but still get a very
inconsistent coating.

Get the most consistent coating using a roller, but application with a
roller creates lots of tiny bubbles.

Read that the addition of salt reduces foaming and bubbling. Added a pinch
of salt to the last tempera mix. It appeared not to foam as much.

I wanted to see what a brush coating would do - no bubbling, and was able to
put on a very thick coating. So thick that it would not bind to the yupo,
or the addition of salt prevented proper hardening.

Didn't have time to do a roller coating though.

Read more about antifoaming agents. Looks like Dimethylpolysiloxane is a
commonly used food grade antifoaming agent. Its seems to be a suspension of
very fine silicone particles that alter the surface tension so that foam
bubbles can not form.

Does anyone have experience with any antifoaming agents?

Gord

---------------------------------------------------------
Gordon J. Holtslander Dept. of Biology
holtsg@duke.usask.ca 112 Science Place
http://duke.usask.ca/~holtsg University of Saskatchewan
Tel (306) 966-4433 Saskatoon, Saskatchewan
Fax (306) 966-4461 Canada S7N 5E2
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Received on Mon Feb 13 13:10:23 2006