Re: I'll never double coat cyano again

On Tue, 7 Jun 2005, roman sokoler wrote:

> by the way - in Post Factory Photography issue #5 - a lot of testing is done
> with single and double coating. Here Cor Breukel says " a dramatic boost in
> print density" with double coating - also my exerience.

Thanks Roman -- in fact if memory serves I'd mentioned that elsewhere as
well. The problem with the current discussion is that (as I noted in
another context last month) there's the assumption of a single definitive
answer, one across-the-board permanent reply available on list about
"double coating" on all papers, in all weather, all levels of spiritual
and physical purity all the time, for all time. Not in cyano, or ever, in
my experience except maybe drink your fixer you will be sorry.

This consistency isn't guaranteed even in "factory" photography where
materials are much more standardized -- as David Vestal has written, he
and friend Ralph Steiner got different tones on factory paper, printing in
the same city, same procedure, same chemistry, though (they hoped)
different water supplies. Obviously in "post-factory" processes, where
nearly every ingredient has its own biography, identical results are less
likely.

I did some of the cyano tests myself, and my students, given the
requirement of two explicated variables tests each semester, did more, not
for any special curiosity re double coating I assume, but that the test is
so easy...

What we all found was .... it depends -- time on the paper before
exposure, of course the paper itself, and temperature/humidity being among
factors. Another interesting finding was that on some papers the second
coat lowered d-max, which looked (casually, not fully explored) to be on
very smooth papers in which second coat (we surmised) wiped off some of
the first. Or possibly also on a buffered paper where more time on paper
is thus caused.

I note also that delay before exposure doesn't always go in one direction
-- depending on temperature, humidity, the paper, and will of the gods,
d-max and contrast, as well as color, can vary.

Ways of applying emulsion can affect results, too -- IME a rod is riskier
than a foam applicator, as rod can lay on too much to soak in, or....
whatever. And of course that, too is another variable (tho foam applicator
can be used to *scrub* -- or to put an eye out for that matter).

As, I believe Chris & Bob Schramm point out, another variable (and on all
points) is the ratio of A to B. Another worth mentioning is combining
A&B... when & how. It is NOT true that you can combine them whenever (as
stated in KOL & elsewhere). If you combine them under safe light and keep
the mix in dark, or safelight, they're OK for several weeks, after which
they will stain (I found). But combine in the light and leave the mix in
the light, exposure time will increase within the hour -- or so my
students found. (I would never myself try such a dumb-ass trick.)

Etc.

Judy
Received on Wed Jun 8 13:15:56 2005