Re: sizing with glyoxal

Ryuji,

This is very interesting...

OK, now let's get my math straight here.

Using a 40% solution of glyoxal, 25 ml per 1000 ml sizing solution which
contains 30g of gelatin, that would equate to 10g glyoxal per 1000ml. You
are saying I only need 1-2% of the GELATIN amount, thus I only need .3 to .6
g of glyoxal which equates to only about 1-2 ml of glyoxal 40%?? I wonder
how I could test to see if this is sufficient hardening for gum printing,
short of sizing a bunch of paper...I have never seen glyoxal in formulas for
gum used in this small of an amount. Have we just always erred on the side
of overkill?

Or am I reading your message wrong?

Chris

----- Original Message -----
From: "Ryuji Suzuki" <rs@silvergrain.org>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Sunday, February 15, 2004 2:18 PM
Subject: Re: sizing with glyoxal

> From: "Christina Z. Anderson" <zphoto@bellsouth.net>
> Subject: Re: sizing with glyoxal
> Date: Sun, 15 Feb 2004 14:03:15 -0500
>
> > It says, from Bostick and Sullivan, "Glyoxal 40% in water"
>
> So you are using roughly 40% glyoxal to gelatin. That seems awful lot
> to me. Much of glyoxal is not bound to gelatin, and this one big
> suspect for the cause of yellowing. Of course, how fast yellowing
> occurs depends on temp, pH, and other factors, such as air contact in
> case of glyoxal.
>
> If you mix 10% glutaraldehyde to gelatin, you get very stiff
> rubber-like solid that looks kinda like a giant eraser. I usually need
> glutaraldehyde in quantity of 1-2% of gelatin to harden my emulsion
> containing 3-8% gelatin in water.
>
> --
> Ryuji Suzuki
> "Reality has always had too many heads." (Bob Dylan, Cold Irons Bound,
1997)
>
Received on Sun Feb 15 18:14:19 2004