Gum bichromate over pt/pd question ....

[scootermm]

Ive been doing a fairly good amount of gum over pt/pds the last few months (thanks to Clay for his informal intro to it)
I usually dont start technical question threads as 99% of the time theres an existing thread about whatever it is that Im asking. In this case, I couldnt find anything in the forum in regards to this.
My question, whats the archival nature of Gum Over pt/pds? Does the Gum Bichromate layer hurt the inherent archival nature of palladium prints? (as Ive read in more than a few counts of the longevity claims of pt/pd prints - even seen first hand a few platinum prints that are 100+ yrs old) Or does is add to its archival nature? or just not effect it at all.

Not something Im really worried about ... as I imagine my growing stack of prints will sit in a draw in some desolate house long after Ive left this earth. But curiosity sparked the thought in my head. Along with a question a fellow photographer asked me about the Gum over palladiums Ive been doing as of late. I sat coating two prints with their 3rd gum layers last night and was again curious about this. (posted one of them in the gallery if you are curious

thanks in advance.

[Jorge]

Dont worry, gum arabic is very stable and should not lower the keeping properties of your prints. Being an organic compound it could be susceptible to fungal growth, pretty much like an Albumen print or a sized salt print. But these cases are rare and happen mostly with poorly kept prints in humid enviroments.

[Kerik]

I agree with Jorge (glad to see you're getting back on your feet). If anything, there may be some slight fading of your pigments over time, but this will have minimal effect on the overall look of the print. The gelatin and gum layers may provide some additional protection of the pt/pd layer from the environment.

[Michael Mutmansky]

The pigment is the biggest worry. As long as you use lightfast pigments, you shouldn't see any problems in a reasonable exposure situation.

I tested a combination gume bichromate and palladium print for lightfastness over about a year and a half, putting half of it in a south-facing window. I could detect no difference in the gum or PD layers, and no yellowing of the liquitex that I normally use to seal the gum layers. The only change I could detect was a slight bleaching of the paper.

So, use lightfast pigments, properly clear the dichromate and you should have no problems with the gum layers.


---Michael

[Jeremy]

yellowing of the liquitex that I normally use to seal the gum layers

Michael, can you explain more of this liquitex sealing you do?

[Michael Mutmansky]

Jeremy,

I have found that the gum layers can sometimes be a bit fragile and possibly prone to abrasion from handling. The liquitex is basically a PVA glue product that is used to seal acrylic paintings. I cut it with water 1:7 about, and dip the prints in the tray for abour 30 seconds and then hang until mostly dry, and then put on a screen to dry completely.

I figure it does two things. It helps even out the gloss differential between highlights and shadow in the gum, and it also acts like a binder to hold the gum together and make it less likely to flake with handling.

It's not necessary to do this step, but it seems to produce a more consistant surface quality for the print, and increases the dmax a little as well on a straight pd print. Since it seems to test out stable, I don't think there is a downside.


---Michael

[Jeremy]

Thanks, Michael, I'll have to look into getting some liquitex and trying this out.

[scootermm]

Learn something new everyday.
I have a bunch of that stuff for my paintings... new use.

Thanks all for the information (both about the liquitex and the inquiry on archival nature)

[Michael Mutmansky]

Jeremy and scooter,

I recommens trying various dilutions of the liquitex. I tried everything from straight to 1:11 and originally settled on 1:7, but more recently I have shifted to 1:9.

The lower dilution, the more gloss the paper picks up. less than 1:4 and the stuff is too thick to be dipping, and will leave a fairly thick coat on the paper.

At that point it's personal preference.

I use the gloss varnish medium, if I remember the name correctly. There's also a matte medium, but I haven't tried it. I doubt there will be much difference at high dilution.


---Michael

[photomc]

Michael, Thank you for the information. A couple of more questions if you don't mind..one is it Liquitex Gloss Varnish? And would this be a good treatment for a traditional Palldium print as well, to give it just a bit of gloss? I know in the past it was dicussed here that one could use wax and there was some discussion about coating a print with albument as well.

TIA for your time.