Gelatin sizing for gum printing and gum-overs...

[Michael Mutmansky]

Folks,

I've been gelatin sizing Fabrianno Artistico EW paper with formaldehyde for years and it works well, but I don't like the smell or the potential health hazards. I do own a proper safety mask for the work, and I have had appropriate ventilation as well.

I am finishing a new darkroom in California, and am getting close to starting up the gum printing again, but I thought I would see if there has been anything new in the sizing realm in the past few years.

A little searching didn't produce anything new since about 2009 or so, and the general conclusion at that time was that gelatin and formaldehyde appeared to be the best approach to avoid yellowing, etc.

Is anyone using anything different these days?

I've tried gluteraldehyde in the past with little success. I think I tried glyoxal as well.

The chrome alum takes too long to harden, so I've never gone that route, and PVA is too fragile for the multi-layer gums I do.

Anyone have any additional suggestions?


---Michael

 

[Andrew O'Neill]

I use dichromate. A few drops of 3% per 25ml of gelatine. Once dried, I zap the sized paper in my UV exposure table.

 

[pschwart]

Folks,

I've been gelatin sizing Fabrianno Artistico EW paper with formaldehyde for years and it works well, but I don't like the smell or the potential health hazards. I do own a proper safety mask for the work, and I have had appropriate ventilation as well.

I am finishing a new darkroom in California, and am getting close to starting up the gum printing again, but I thought I would see if there has been anything new in the sizing realm in the past few years.

A little searching didn't produce anything new since about 2009 or so, and the general conclusion at that time was that gelatin and formaldehyde appeared to be the best approach to avoid yellowing, etc.

Is anyone using anything different these days?

I've tried gluteraldehyde in the past with little success. I think I tried glyoxal as well.

The chrome alum takes too long to harden, so I've never gone that route, and PVA is too fragile for the multi-layer gums I do.

Anyone have any additional suggestions?


---Michael

Sandy has been using dichromate with good results for carbon transfers. This isn't really practical given the variable weather in San Francisco, so I am sticking with formalin. A really tiny amount of formalin works for me -- a couple of drops per 8-1/2x11 -- so fumes aren't much of an issue any more. Has anyone tried albumen for gum over? This is easily hardened with isopropyl and it dries very quickly.

 

[Michael Mutmansky]

I've never tried the dichromate approach. Does it crosslink the gelatin in the same manner as the gum? I'm wondering if there is a potential problem having dichromate in the gelatin and also in the gum (that is, the gum layer may crosslink (fog) a little because of the exposed dichromate in the gelatin migrating to the gum layer.

How long of an exposure in the UV unit?


---Michael

 

[pschwart]

I've never tried the dichromate approach. Does it crosslink the gelatin in the same manner as the gum? I'm wondering if there is a potential problem having dichromate in the gelatin and also in the gum (that is, the gum layer may crosslink (fog) a little because of the exposed dichromate in the gelatin migrating to the gum layer.

How long of an exposure in the UV unit?


---Michael

Here is Sandy's doc: Dead Link Removed

The dichromate does crosslink the gelatin, which is why dichromate has been the standard sensitizer for carbon transfer, collotype, and Rawlins oil prints. Once the sizing layer has been sufficiently exposed there should not be any problem with the dichromate hardening subsequent layers.

 

[Michael Mutmansky]

Thanks Peter...

I'll look into this a bit and try the dichromate method along side the formalin approach and see which one seems to work out better.

---Michael