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

RE: brush vs tray size for gum


I agree that tray sizing is a lot of mess and hassle for no substantial
benefit. Plus, why do the sizing in 2 steps when it can be done in one? I
use either a glass rod (puddle pusher) and/or a brush.  I add the hardener
(formaldehyde in my case) to the sizing just before sizing each print.
Three drops of formaldehyde and 5 ml of 3% sizing easily does an 8x10 to
11x14 print.  In these tiny amounts, exposure to formaldehyde (or whatever
hardener one uses) is minimal. I get very even sizing this way. A little
bit of curl to the paper, but nothing that causes any problems.

I tried B.M. glut and did not like the results. It resulted in slower
development and considerably more staining than with formaldehyde.

As for sizing with unhardened gelatin, that sounds like another in a long
line of T King's erroneous hyperboles.

Speaking of gum, I taught a gumover workshop in Philladelphia this past
weekend for www.projectbasho.org. On sunday it was 80 degrees F and 82%
humidity in the darkroom. That's the first time I've printed gum in
sauna-like conditions and it created some hassles with very slow
development and the need to intervene with some brute force measures
(brushes, fingernails, sandpaper). Anybody have similar problems printing
gum in high humidity?  The conditions seemed to cause problems with the
sizing in particular because development was much closer to normal when I
did a single coat of gum on unsized paper right out of the plastic bag. I'm
speculating that the humidity either prevented the gelatin from hardening
completely or it allowed the gum solution to soak into the sizing a bit
rather than sitting on top. Despite the problems, I believe a good time was
had by all. Although I always want things to go smoothly during the
workshops, it's good for the students to learn how to deal with problems
when they come up.


Original Message:
From: Christina Z. Anderson zphoto@montana.net
Date: Tue, 26 Sep 2006 08:08:22 -0600
To: alt-photo-process-L@usask.ca
Subject: brush vs tray size for gum

Hi All,
This weekend was time for sizing paper, and since I was doing small sizes 
(11x14's) I decided to tray size instead of brush size to see if it had any 
added benefits to brush sizing.

I was sizing with gelatin glutaraldehyde as usual.  I did use a piece of it 
right away, same day, and had no problem with the sizing not being hardened 
and producing "magenta squares" as did Carmen.  However, I was using glut 
that I bought from a medical supply house (now available at the 
Photographer's Formulary) and not Black Magic.  The gelatin on my paper was 
not slimy in any way so I know it was hardened. I am still not sure why 
Carmen got that problem, and am wondering about the suitability of Black 
Magic, therefore, with its added sulfite. It sounds like the same result I 
had when I tried Terry King's advice to use unhardened gelatin and got

With tray sizing and cautions with glut, I gelatin sized the paper first, 
and then the next day I soaked the sized paper OUTSIDE in a tray of 50ml 
glut to a gallon of water.  That worked well, but I would only tray size if 
the hardening part could be done outside to minimize fumes produced by the 
surface area of a whole tray of hardener, whatever type--glut, gly, 
formaldehyde. (When I brush size I keep the solution capped inside a
and pour out a cup at once.) The gelatin paper went in "slimy" feeling, and 
went out unslimy.

The paper works fine but I learned a couple things:  paper tray sized with 
gelatin will sink to the bottom, not float as does brush sized paper
Arches) so if I am going to leave the paper soaking for a while it needs to 
be face up. I learned that the hard way. Back to floaters and sinkers, Mark.

The paper does curl less than brush sized, but it doesn't seem worth the 
added trouble of trays. This is the only benefit I can see.  Oh, maybe more 
evenness of sizing?  I don't know this one yet...will have to print all 

My husband set up an ingenious "clothesline" for me--a rung ladder on its 
side has plenty of hanger-ready rungs.

I learned another thing the hard way:  I printed 4 prints on the unsized
shrunk paper with a cyanotype layer, put the paper through the hot gelatin 
sizing process and didn't THINK that the 140-whatever degree gelatin would 
shrink the paper even more and make registration a B---H but you bet it 
did--warped and shrunk. Luckily only 4 prints ruined. DUH. Or, as Clay

The bottom line is that brush sizing is sooo much easier and works well and 
uses way less gelatin--I sized 24 11x14s with a a liter of 3%, and normally 
I can do that many 16x20s with the same. I don't think even with small
I would tray size...

That's all my truly exciting weekend experience!


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