Archived posting to the Leica Users Group, 1998/12/14

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Subject: Re: [Leica] Kodachrome- Scmodochrome!
From: "Dan Post" <dwpost@email.msn.com>
Date: Mon, 14 Dec 1998 22:00:52 -0500

The Kodachrome process is a strange one, and unique. It does use dye
couplers, but unlike other transparency materials which have the couplers
hooked to the silver halide molecule, the Kodachrome couplers are diffused
into the emulsion at the time of processing.
This process always was critical, and expensive. The coupler for the yellow
dye alone layer ran at something like $1200 a pound twenty years ago, and
the process of using and recovering the couplers for reuse took the services
of a full time chemist.
The fact that the large coupler molecule was not hooked to the silver halide
complex made for higher acutance from thinner emulsions, and a higher
density of smaller grains. I had heard that the two musicians who invented
the process used to time it by humming a certain piece of music. My feeling
was that the only reason that the whole thing worked at all was the same
reason a bumblebee can fly- nobody ever told any of them that it wouldn't
work.
I like Kodachrome, but personally, I think color perception is akin to, say
the perception of sound- specifically music. Some people, blessed 'tone
deaf' to many color renditions are satisfied with the results, whereas some
one more sensitive might be able to catch subtle changes. This is one of the
reasons I use a densitometer to strictly set up our lab when I open. Our
test prints in the morning look good to me up the the point where the spread
in densities approaches .05 or .06. Some people can tell if it's .01 off!
I also realize that when we see, say, red, that we cannot really be sure
that what we see is perceived by another in the exact same way. I call it
red, and you may call it red, but you can never know exactly what I am
seeing. This was impressed on me by have a color blind friend who was not
'totally' color blind. He could tell some values of red and green apart, but
at some point, certain shades of red and green were perceived by him the
same as a   shade of brown.
My feeling is that if an emulsion doesn't suit you, find another. Years ago
I routinely used an 81A filter to warm my Ektachrome shots so they'd look
more like the Agfachrome results I got then- nice warm tones, and snappy
contrast.
Here again is a case of different strokes for different folks.
Any others out there with the same feeling? Or am alone out here in the
O-zone?
dwpost@msn.com