Re: Glyoxal?

Christina,

I'm not sure I understand which one to use with the recipe you give in the
first paragraph. I'm surprised with all this, only 0.15 gram of the stuff
for a liter of gelatine, it doesn't seem like much. I suppose as long as it
does the job

Thanks for the excellent info,
Yves

----- Original Message -----
From: "Christina Z. Anderson" <zphoto@montana.net>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Friday, January 13, 2006 7:58 PM
Subject: Re: Glyoxal?

> Yves,
> Sorry, I must have missed this post.
>
> There are a few ways to harden--formaldehyde, glutaraldehyde, alum,
glyoxal.
> I suggest doing an archive search for those 4 items. You will find lots
of
> discussions and formulas for these in the last several years, and some
good
> formulas. Some use alum quite regularly, formalin is used a lot, the
> newcomer on the block is glut with not enough data to give you a yay or
nay.
> Just that I use it always, and I am teaching it this semester to my
> students, too, and I know of at least four others that are having great
> success with it as a hardener. that is 6ml of 2.5% added to 1 liter of 3%
> gelatin.
>
> I think all of the hardeners have toxicity and cautions...use extreme
> chemical practice with these because since they harden colloids they
harden
> eyeballs. When I teach sizing this semester I will add the glut to the
mix
> myself and not let unwary students fool around with it, to be safe. You
> know, though, with how people treat superglue like it's no big
deal....makes
> you wonder.
>
> Those that don't get yellowing with glyoxal seem to usually harden, and
then
> rinse after hardening right away or something of that nature. Or use the
> paper quickly.
>
> Personally, if I wasn't using glut I would go to formalin before glyoxal.
> It's worked for centuries--well, 1 1/2 centuries.
>
> chris
>
>
>
> ----- Original Message -----
> From: "Yves Gauvreau" <gauvreau-yves@sympatico.ca>
> To: <alt-photo-process-l@sask.usask.ca>
> Sent: Thursday, January 12, 2006 6:46 PM
> Subject: Re: Glyoxal?
>
>
> > Thanks Christina,
> >
> > are there other ways (other stuff) to harden the gelatine without
causing
> > a
> > change in color and I assume doing all of this we must keep a neutral ph
> > or
> > whatever is best for archival.
> >
> > Regards
> > Yves
> >
> > ----- Original Message -----
> > From: "Christina Z. Anderson" <zphoto@montana.net>
> > To: <alt-photo-process-l@sask.usask.ca>
> > Sent: Thursday, January 12, 2006 4:11 PM
> > Subject: Re: Glyoxal?
> >
> >
> >> but I don't bother to rinse
> >> > as a step in the sizing process because the development bath in the
> >> > gum
> >> > process restores the paper to the original pristine white. So I
don't
> > see
> >> > any necessity for a separate rinse. But you'll need to see if that
> > works
> >> > with your paper, or not.
> >> > Katharine
> >>
> >> Yves,
> >> Sorry to disagree here but there are a number of us on the list that
> > cannot
> >> get that stain out no matter how much we soak it, breathe on it, sit on
> > it,
> >> look at it. You can do what you want, but don't say we didn't warn you
> >> :)
> >> If I wanted a dull ivory paper to print on, I would have bought it that
> > way
> >> to begin with. It is unacceptable to me, but you may be one of the
> > blessed
> >> ones that don't get glyoxal yellowing. Pretty soon on my website I
will
> >> have an image of glyoxal yellowing to show you what I mean. However,
my
> >> guess is it is paper dependent, and perhaps related to my paper choice
> >> coupled with my water supply. The point being, for some of us the
yellow
> >> does not disappear once it is there.
> >> Chris
> >>
> >
> >
>
Received on Fri Jan 13 22:12:56 2006