From: Judy Seigel (jseigel@panix.com)
Date: 12/28/00-01:34:09 PM Z
On Wed, 27 Dec 2000, Sarah Van Keuren wrote:
> ....A distinction I make that Judy may not make is between
> an emulsion and a chemical solution. P.O.P. with silver chloride salts in a
> gelatin coating is for me an emulsion. Gum bichromate with pigment suspended
> in sensitized gum arabic is also an emulsion. The trick with syrupy
> emulsions is to attach them to the support but to keep them on the surface
> of it. Cyanotype, vandyke, palladium, platinum and ziatype are all chemical
> solutions, watery mixes that soak into the fiber of the paper....
Sarah, you forced me to get up from this chair & consult dictionary, which
after "a milky fluid made by rubbing almonds with water" gives, for
emulsion, "an intimate mixture of two incompletely miscible liquids" -- by
which definition it sounds like you're right -- gum and silver salts in
gelatin may very well be emulsions, the others (sound like) solutions.
Of course as several "alt" books (now lost in mists of time -- maybe KOL?)
point out, people CALL them emulsions, & many (most?) of us have the
habit. Maybe our usage has even changed the meaning -- as language does
change.
But maybe we *should* stress the distinction as you suggest... the
difference between sinking into the paper (cyano, etc.) and sitting on it
(gum, etc.) surely affects coating, developing, clearing, etc.
> ....I think it
> helps those who are learning alternative processes to understand this
> distinction. Does anyone else find this a helpful distinction?
Of course some of those "emulsions" may do some of each (???), but the
point is well taken, the distinction may deserve more attention than it's
had. On the other hand, *making* that distinction gives us teachers ways
to make even MORE mistakes than we do already (a dangerous profession).
best,
Judy
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