Fixer hardener to harden Gelatin Sizing for Gum Prints??

Hello everyone,

I am looking for a way to harden gelatin sizing in gum printing. I have tried Glyoxal and it is nasty stuff. My roommate took a class a few years back where they hardened thier sized paper with Kodak fixer hardener. She doesn't know what formula they used.

I am hoping that someone out there knows the formula. I would love to try it!

Thank you!

Never had a problem with formalin. Nothing in gum printing is more nasty than dichromate.

The standard Kodak hardening fixer is F5 - You'll find a recipe for it (and others) filed under (there was a url link here which no longer exists).

I prefer to add around 20ml of 2% potassium chrome alum per litre of 0.7% to 1% gelatin solution. Or soak already sized paper in a 1.3% formaldehyde solution.

Hello all,

Thank you for the replies.

Unfortunately I am running a darkroom at a university and we are not allowed to use formalin or formaldehyde. The administration does not like to idea of using glyoxal as a hardening option as we don't actually know if it is any "healthier" then using the banded hardeners. There are reports the glyoxal treated paper "fumes" long after the paper has been treated. So I am searching for something else. Currently we are having students use scotchguard which works, but is far from perfect. I would like to use gelatin sizing and then harder. When someone mentioned using Fix hardener (part B of film fix) Kodak Cas# 1733013 I was very excited. So, if anyone else has heard of this I would greatly appreciate any recipe that you may have.

Thank you!

I don't have the formula for the Kodak part B, I know that it has potassium alum. Christopher Walrath just post the formula for Ilford IF-13 fixer hardener, which should be similar.
(there was a url link here which no longer exists)
I have not used this for hardening the gelatin for gum printing, so no first hand experience there.

I harden my gelatin with chrom alum as suggested by Paul, by adding it directly to the warm gelatin. My instructor for gum printing ( also a Univ professor ) did not have us hardening our sizing. It was simply 3 packets of Knox gelatin to 1 liter water. I found I could get three layers of gum down on my unhardened sizing, but the forth layer frequently stained.

A non-toxic alternative that I do use regularly is Gamblin PVA Sizing diluted 1:1 with water. I have used it on shrunk Rives BFK for gum. And also between the 3rd & 4th layers of gum on unhardened sizing.

Thanks for the tip.

But, I looking for a different formula. I have plenty of Kodak part B, actually tons. I am wondering what and how to mix it with, if at all to harden the gelatin.

Thanks!

Hardening gelatin and fixer - sounds like a PM to PE (Private Message to Photo Engineer) asking if he can chime in on this might be in order.