Re: ferri sesquichlorati
Hi Chris, Yes fun :-) If you do anything with it at some point, I would like to know. I have mostly been over at the Carbon list for a long time, but studies slided over into kind of gum recently so "moved" back here, so have missed that dichromatype, but will do a search. (page 174 in Kosar describes a silver system for "carbon" or relief images, I also have an article somewhere dealing with that, it could maybe also work with gum, but is probably a mess to get too work :-) It is somewhere far down on my to do list.. Thought I should try to mix some liquid light and pigment and see what can be done as a start...) Have seen a brief descriptions of ferric used as a crosslinker for holography with PVA.. But have yet to chase down the references.. BTW, Is there a maximum number of layers for gum, one book I have claim twelve or so, but have seen other claims of 20 .. ? Halvor On 10/21/06 12:08 AM, "Christina Z. Anderson" <zphoto@montana.net> wrote: > Halvor, > This is really fascinating... > > First of all, I found the quote: "...earlier observations by Alphonse > Poitevin in 1863, that ferric salts cause gum and similar colloids to harden > and become insoluble in water, whereas ferrous salts do not." p. 53 Ware, > Cyanotype. > > I had heard this once before on the list--I think Judy brought it up a long > while back--and thought it an interesting phenomenon, but didn't know where > it came from until you brought it up. > > I dunno, might just try mixing a bit of A and B and plopping it in my gum > solution as per normal--it'd have the dichromate in it to harden, and the > cyanotype would just get exposed at the same time? Might be worth a try. I > never thought about this until China Hamilton talked about adding the silver > nitrate to the mix--a dichromatype he called it. > Chris >
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