Somehow, I saw this coming;-)
The first color printing process was Du Hauron's carbon process of 1868.
Strictly a lab curiosity at the time, results were not entirely convincing,
in part because of the lack of true red-part-of-the-spectrum sensitizers,
until Vogel's work much later. Du Hauron's yellow-magenta-cyan (actually
more like yellow-red and blue back then) were developed and assembled on
mica sheets and bound together. I have a copy of his original French
patents here.
In 1905, the N.P.G. (Neue Photographische Gesselschaft) process was
introduced in Berlin. This made use of thin celluloid supports and the
pigmented images (produced by exposure through the support) were
transferred and registered onto paper. This process was used successfully
by the Dover Street studios of London among others.
Let us keep in mind here that the first *very* successful process that
launched color photography was the Autochrome, a three-color additive
mosaic screen process, introduced in 1907.
It would take a thesis to explain my train of thought, based on an
understanding of the various inventions that came and went through the
years, e.g. Bennetto's carbon process (1898); Raydex (1913); Tricolor
Carbro (1920s); Raylo (1923); Duxochrome, a process similar to today's
Evercolor, i.e., with silver bromide part of the pigmented emulsion (1929);
Vivex (1931), Devin (1937; later McGraw); Carbro-Chromatone (1937),
Belcolor (1940s) Dufaytissue (1940s) Koloroid (1950), etc. (BTW the basic
principles, patent numbers, etc. of all these early methods are described
my Encyclopedia)
At one point, it became evident that the best carbon method (we keep carbro
out of the equation here) was the double transfer process. This is very
obvious, as anyone using the process uses the quick and dirty single
transfer technique to evaluate proper exposures, but then uses the double
transfer approach to make the final print. This saves a lot of work but it
is always pretty awful as the first layer down is yellow and it is very
difficult to manually register the next color on top of that with the
traditional method. The surface of the print also carries every single
scratch and other defects off the plastic carrier, etc...
Suffice to say that "true carbon", IMO refers basically to the
"traditional" method making use of (1) the "double transfer" technique,
with manual registration, with (2) three continuous tone negatives on (3) a
real paper base.
This would be the best process to reproduce Autochromes for instance. The
only problem is that it is not commercially feasible:-(
On the other hand it is "artistically" feasible.
>>The newer approaches typically use pre-sensitized pigmented papers on
>>*stable* polyester supports with automatic registration and direct
>>development, one on top of another.
>
>Our "tissue" is not pre-sensitized. We hand expose and pin register each
>color and dry between each transfer.
I know that (I've been following Berger since the 70s) and this is why I
wrote "typically" above as both of your competitors use presensitized
materials.
..
>>The problem here is that Wilhelm in his recent book, indicated that $1.99
>>prints on the right RC paper (of all things!) can last over 100 years while
>>$199 prints can last 300 years and many people are not willing to pay the
>>difference to see their wedding pictures or whatever last that long;-)
>
>The market for Rolls Royce is smaller than for the Chevy. They are both
>cars that work, and use the same gas. There is a market for quality and
>uniqueness. Is it big enough to sustain a business? I guess only time
>will tell.
Years ago I bought the poor man's version of the Rolls Royce, a Rolex. My
$10 Casios keep better time but I throw them away every three years. The
Rolex is still ticking. There will always be a market for everything.
Luis Nadeau
awef6t@mi.net
nadeaul@nbnet.nb.ca
http://www.primenet.com/~dbarto/lnadeau.html#A0