U of S | Mailing List Archive | alt-photo-process-l | Re: brush vs tray size for gum

Re: brush vs tray size for gum

From: "Christina Z. Anderson" <zphoto@montana.net>
Subject: Re: brush vs tray size for gum
Date: Tue, 26 Sep 2006 19:06:17 -0600

> I have always felt glut hardened instantly, because in my experience
> the paper is usable right away.

I agree.

> But Carmen's experience with glut and a magenta square (using Black
> Magic glut, though) made me question the possibility of glut needing
> "aging".  If I remember correctly, Ryuji concurred that glut doesn't
> need aging time.

I am not sure about Black Magic hardener for your application, since
it also contains sulfites (and maybe more) that can (and quite
plausibly) interfere with dichromate chemistry. You, Don and Sandy
have glut that I prepared and use for my purpose. If these work fine,
but not the BM hardener, my suspicion goes to the additives and
difference in formulations.

> Mark, as far as bubbles and a roller--I used a dollop of Everclear
> in my size to get rid of bubbles.

I have tested dozens of surfactants and antifoamers... some are quite
good than others. I have one for final rinse solution for films and
plates, a few for emulsion coating, etc. BUT as far as I know most of
these useful agents are ONLY available in full drum sizes and I
realized this is probably why good agents are not used by most users.

> BTW, does anyone on this list work with cadavers and aren't they
> soaked in formaldehyde and does one have to wear gas masks while
> working on them? I would think a whole body soak of the stuff would
> fume off a lot more than a bunch of sized paper...but one of these
> days I was going to try Kerik's method of drops of
> formaldehyde--such a quick and classy little method...

I've dissected human cadavers twice. I don't know how they perfuse the
human cadavers, but usually body is perfused with fixative (typically
4% formaldehyde, i.e., 10% formalin, or 3% formaldehyde and 1%
glutaraldehyde, both buffered at pH 7.4). However, once the tissue is
well fixed, I don't think they apply more fixative. Those dissection
rooms have sprays to keep the tissue wet, but they are not fixatives
(dry tissue is hard to dissect and also hard to look at). If I go
there again I'd look at the labels carefully but at that time I didn't
really care...

I also handle tissue fixed in glut and formaldehyde routinely, but
this is done in fume hood. Note that the fixative is stronger than
your hardener, and at higher pH (more reactive), and I use a couple
hundred milliliters at a time.

Perhaps one big incentive for anyone to go on diet is to experience
dissection and learn human anatomy. In my memory, fat is the worst
smelling part of the fixed body. (Lean male cadaver is most popular in
dissection class!) But watch out for too much weight loss if you want
to be a fashion model in Italy...