From: Judy Seigel (jseigel@panix.com)
Date: 01/13/02-12:56:22 AM Z
On Sat, 12 Jan 2002, robert wrote:
> 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
You may be mixing apples & bananas here... The diazo used for silk screen
is (I would assume) used for making the screen, not the final image, which
would be some kind of ink. It's my understanding that the diazo fades...
or at least the early books said that. I would also take the fact that
there's no entry for diazo in Chris James's *very* comprehensive book as
due to some reason besides ignorance. Diazo is I believe used as a direct
printing process, for commercial use where archival isn't an issue, but
not in silk screen.
All that remains in the gum print is pigment & hardened gum arabic, said
to be as archival as the paper, as platinum, even, assuming the pigments
are archival.
Judy
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