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 also size papers for gum using 3-5% solutions and adding just a bit of Formaldehyde to the solution just before coating. I used to use a brush, but this caused a lot of bubbles. I switched to a threaded rod, which I heat before running it over the solution, and this completely eliminates the bubble problem because the warm rod dissipates the bubbles on contact. This is a technique that I adopted from coating carbon tissue.

I am using more solution per given paper area than would be required for gum printing, but I think this should not matter in practice.



The largest print I've sized is 20x24. But, if I was going to do 22x30, I
would make a 22" glass coating rod and apply the sizing with the rod, then
use a brush to fix any areas that were either too thin or too thick. This
makes the process go very quickly so the gelatin doesn't have the chance to
harden. I would also use formaledehyde rather than glyoxal to prevent
yellowing.  When using a glass rod, first place a towel on the table
underneath the paper. This will greatly help keep the rod in good contact
with the paper, especially for larger prints. I would guess about 30 ml of
3% gelatin with 18 drops of hardener would do it.


Original Message:
From: Carmen Lizardo carmenlizardo@yahoo.com
Date: Tue, 26 Sep 2006 12:51:12 -0700 (PDT)
To: kerik@kerik.com, alt-photo-process-l@usask.ca
Subject: RE: brush vs tray size for gum

Dear Chris and Kerik,
I would love to brush size my paper, specially because
use a full sheet of 22x30 inches when I print, and you
could only imaging how long that takes and how much
gelatin I need, but I can't seem to be able to get an
even coat, and mixing glyoxal and gelatin together is
out because I have to able to rise it off the gelatin
to prevent yellow stains.  Of course when I used Glut,
it was from black magic and that did not work. I also
felt it in ky eyes and throat and i not even the
sensitive type.  I am willing to try again, maybe with
a different glut?? Any pointers that you can give me
with the brushing??  I was thinking that it had to do
with the size of my paper. The gelatin gets hard
before I have time to cover the whole 22x30 sheet.
Thank you kindly,

--- "kerik@kerik.com" <kerik@kerik.com> wrote:


 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

 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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