Re: gum bichromate

Judy Seigel (jseigel@panix.com)
Sun, 11 Jun 1995 02:41:46 -0400 (EDT)

On Sat, 10 Jun 1995, Luis Nadeau wrote:
> >Also, Gini may be using ammonium dichromate, which is a more saturated
> >saturated solution than potassium.
>
> Not necessarily. You can make a 1% sol. of ammonium dichromate, and a 4%
> sol. of potassium dichromate...
>
> Gotcha!

I hate to be the bad guy & disappoint Luis, but you don't gotcha-me on
this one.... Gini had mentioned "saturated solution," though she
didn't say saturated of what, and
everyone else (until Sam Wang) was talking saturated solution.

> P.S. The gum process is much more forgiving than the carbon transfer (& the
> gravure resist). Look up the words "spontaneous hardening" in the index of
> any book on carbon printing.

Yes, gum is not just forgiving but sensitive (the perfect lover).
So the question is, why do carbon? (I've never done it, though I've read
many books on carbon -- including Luis's.) I'm throwing you a soft ball,
here Luis --- why is it worth it? Is it?

Judy