From: robert (robert@RobertSchaller.net)
Date: 01/12/02-01:58:56 PM Z
on 1/12/02 9:42 AM, BobWicks@aol.com at BobWicks@aol.com wrote:
> Dave:
> Diazo salts is the most recent application to replace bichromate that I have
> heard of. I do think the light sensitivity is slower. It is currently being
> used in the silk screen industry and it reacts in the same manner that
> bichromates do on amino acid chains. As you may know bichromated salts make
> any organic material sensitive to light. Where the light strikes the
> emulsion, amino acid chains are formed and they are insoluble. Diazo works
> in the same way but is safe to use and to the best of my knowledge it is not
> toxic (so the companies say).
>
> Bob
Dear Bob,
Thanks. This is certainly intriguing. It raises two groups of questions
for me: which diazo salts, exactly, and where would one get them? And how
about the gum part -- how much, what exposures, etc.? That is, if anyone
has done it and is willing to share.
Secondly, that dichromate (or diazo) works by cross-liking amino groups on
exposure to light answers a fundamental question about the mechanism
involved. Is there a good source anyone could recommend for this chemical
information? And also, exactly which frequencies of light are most
effective for either substance?
Robert Schaller
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