From: Monnoyer Philippe (monnoyer@imec.be)
Date: 09/03/02-06:51:52 AM Z
Hello Kees,
This additive is a reactive surfactant, understand that this will be more efficient then a surfactant. The z-6040 is an epoxysilane. That substance molecule is constituted of two ends separated by a carbon chain. One end reacts with the amino acids of the gelatin (or colloid). This first step links that surfactant to the gelatin macromolecules. At this stage, a small part of the gelatin becomes a modified gelatin with no (or frankly neglectable) influence neither on photographic characteristics nor on conservation of the print. That kind of surfactant was (and maybe still is) used in the photographic industry to make silver halide photo plates.
The other end of the molecule is a silane function. This part will adsorb preferentially on the glass surface. Knowing that the other end is chemically attached to the gelatin, when the silane end sticks to the glass, it means that the gelatin itself sticks to the glass.
There should be no residues left in the emulsion. You only use clearly less then one percent of the total volume of your emulsion (I used 0.2 ml per 100 ml emulsion if I remember correctly).
Do not forget to read the safety datasheet and product datasheet from Dow Corning. You can find it here
Safety Data Sheet: http://www.dowcorning.com/DataFiles/090007b28042e07e.pdf
Z-6040: http://www.dowcorning.com/applications/Product_Finder/PF_details.asp?l1=006&prod=01011278&type=PROD&pg=00000261
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GLASS|silane/\/\/\/\/\/\Gelatin
|
About very stable images on gold, why not trying chrysotype on gold ? Platinotype wouldn't work because, as Pt is more noble than gold, it would darken immediately on the gold surface (with the gold being oxidized). But chrysotype might work fine. You will probably have to add a thickener to coat the gold surface. 0.5% gelatin or gum or PVA ...?
Have fun,
Philippe
|-----Original Message-----
|From: Kees Brandenburg [mailto:info@co-web.org]
|Sent: Tuesday, September 03, 2002 14:08
|To: alt-photo-process-l@skyway.usask.ca
|Subject: RE: silane
|
|
|Hello Philippe,
|Do you know of this 'additive' is safe from a conservation point of
|view. Are there any residues left in the emulsion that can react with
|the colloïd or image particles (either silver or pigments, like in
|gum)? I'm still searchimg for a method to get a very stable image on
|a metal (gold) surface.
|
|
|Kees
|
|
|
|
|>Well yes, I thought it was obvious. Indeed, one has to mix it with
|>the emulsion before coating.
|>
|>Philippe
|
|--
|
|
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