Re: Gum & the commercial ?
On Fri, 3 Nov 2006, Sandy King wrote: [re Chloral Hydrate] I don't know what it is but you can only get it with a prescription. Back in the days when I was printing gum I convinced my dentist it would be good for my teeth and got a bottle of it. If you have any need of it I probably still have it somewhere in my chemistry stash. Used as Watzek recommended it hardens the gelatin slightly making it necessary to develop with some type of force, say by water spray or scrubbing. I never managed to get it right, however.I also got some chloral hydrate and found it didn't do what the old formula said... And yes it's tightly controlled today -- but couldn't be gotten in "pure" form in any event ... just "formulated", with, I suspect other ingredients that may affect results negatively. I assumed they did, also that the version available was anyway weak. (In olden times everybody was taking "laudanum" and all sorts of opiates for toothache and everything else, so maybe it took a really big dose to get through to them.) From memory -- it was at least 10 years ago -- the idea was that the gelatin would be soluble at room temperature with the chloral hydrate added so that.... maybe the idea was a gum print made with gelatin, not gum arabic, but anyway it didn't. I doubt the chloral hydrate from, say, CVS, is what was used back in the day... But my experience is that MANY of the the special ingredients (manganese sulfate et al) lacked effects we can see today. I suspect that in the days before the 21-step & similar objective tests, a lot of "effects" were in the eye of the beholder. (Including the paper from a certain cyano toning method turning bright yellow -- presumably copied from some old source in KOL and from there almost verbatim by Hirsch in "Photogrqphic Possibilities." It never happened, I promise (as described P-F # 7, page 36, ff). Judy
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