[Alt-photo] Question: Gum Printing on Wood Problem

udo.schnitzbauer at uzh.ch udo.schnitzbauer at uzh.ch
Wed Aug 30 05:00:08 UTC 2017


Dear List, 

since a while I am trying to print single color gum (black pigment) on wood, without no success like Massimo Attari does it:
https://www.youtube.com/watch?v=BSPEKlahj2I

First I do not get this completely black layer, like him. If I try it with more pigment, gum, more layers and so on after exposure the layer will detach from the substrate. 
Even if I size with 3% gelatin hardened with glutaraldehyde or formaline. A trial with a first plain layer of gum/dichromate was unsuccessful, too.
I am now a little bit "stumped for an answer" (in German: überfragt).

But I think there is a solution what I found accidentally: I used for a trial the Cyanotype-Recipe from Joseph J. McAllister at page 10 http://roaring20sevent.com/wpe/downloads/glass%20cyanotypes%20processv2.pdf with gelatin. I forgot that it´s important to workup the print shortly after the emulsion is fan dried and let the plates sit over night for drying. The result was a dark reaction of the cyanotype-gelatin-layer which reacted to a completely black color. Hoping for some rescue I exposed it with the negative for 10 min under UV and give them a water shower. Nothing happens, disappointment....but for recycling of the wooden plates I used hot water (50-60°C) to get rid of the gelatin layer and suddenly it worked. The layer showed more or less the same behavior like the gum layer in the video.
Here are the results:
Right the first accidentally happened result and left the second trial for confirmation:
http://illumina-chemie.de/gummidruck-bzw-gum-bichromate-t4096.html#68602

So I will make a few more trials....


Bj68




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