[Alt-photo] DAS (was Re: Luis Nadeau)
workshops at polychrome.nl
Thu Oct 26 12:52:55 UTC 2017
I have been looking into this vegan/vegetarian pigment colloid printing options too. It's hard to find a good gelatin replacement for carbon because gelatin has such nice characteristics like reversable gelling, swelling, and solid gel liquid transitions at just the right temperatures. Just to mention a few.
DAS also hardens some synthetic colloids very well. I got a very very sensitive mix with polyvinylpyrrolidon (PVP) even with extremely low DAS concentrations. It needs further testing though.
DAS is considered much safer than dichromates. It is flammable and light sensitive though and the powder needs all common safety measures like dust protection and gloves. I always mix a quantity of 3% saturated solution and keep that in a brown bottle in my darkroom. The powder goes in a lighttight container in the fridge or freezer. There it will keep for a very long time. The solution keeps very well too at room temperature.
On 26 okt. 2017, at 02:16, Joseph Smigiel <smieglitz at gmail.com <mailto:smieglitz at gmail.com>> wrote:
> Thanks Kees.
> May I inquire further why you found DAS unsuitable for gum printing but not carbon or casein? FWIW, I became a vegan a couple years ago and will not be doing casein printing so I am looking for a safer alternative for gum printing. I also had planned on using exposed, unpigmented, dichromated, gum as a sizing in place of gelatin but would prefer a safer alternative for that purpose too.
> Any further information on your gum printing tests would be greatly appreciated.
> p.s., I'm finding conflicting (M)SDS sheets on the substance. One manufacturer (Sigma-Aldrich) indicates it is "not a hazardous substance or mixture" while others (TCI, Spectrum) characterize it as much more hazardous
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