[LargeFormat] Re: WWII Signal Corps newsgroups

[Richard Knoppow]

----- Original Message -----
From: "Les Newcomer" <lnphoto@twmi.rr.com>
To: <largeformat@f32.net>
Sent: Friday, January 03, 2003 7:20 AM
Subject: Re: [LargeFormat] Re: WWII Signal Corps newsgroups


> I maybe wrong, but the dye transfer process was common in
the advertising/
> photographic business through the 80s as a way of making a
print.  RIT was
> still teaching dye transfer in '88.  I've never used the
process, but an
> old ad exec told me it was THE way they were able to
montage backgrounds
> and foregrounds and other things that Photoshop does now
with three clicks
> of a mouse.
>
> Les
>
>
> On Friday, January 3, 2003, at 05:29 AM, Diane Maher
wrote:
>
> > The dye transfer printing process was continued until
the mid 1970's.
> > Technicolor is trying to reintroduce the printing
process now.
> >
  The dye transfer process in one form or another dates from
very early. Kodak bought the process from another company
and introduced it as the Eastman Wash Off Relief Process
sometime around the mid 1930's. A modified version announced
after WW-2 was called the Kodak Dye Transfer process. The
Technicolor company used essentially the same process, which
they called Dye Imbibition as their principle method of
printing until the mid to late 1970's.
  Kodak discontinued materials for Dye Transfer about a
dozen years ago. However, someone else is offering the
materials. I would have to do some searching to find them.
  The dye transfer process consists in making gelatin
matrices for each primary color. The method can be either
the familiar dichromate process or the use of a tanning
developer on a soft gelatin silver emulsion. The latter was
used by Eastman Kodak. The matrices are exposed to color
separation negatives. In the latter version of Kodak's
process panchromatic matrices were available for direct
printing from color negative film through separation
filters.
  One the matrices are exposed and developed they are washed
down with hot water which melts off the unhardened gelatin.
This leaves a matrix of gelatin in the form of a positive
image. The matices are then soaked in a dye solution,
rinsed, and pressed against a final gelatin coated carrier.
  The process is complex but not beyond doing in a home
darkroom. The resulting prints are of excellent quality and
good sharpness. Dye transfer prints were widely used for
commercial purposes, display prints, and for originals to be
used for photomechanical reproduction. Digital pre-press
killed it off.
  Another but more difficult process once widely used for
high quality color is the three color carbro process. In
this three carbon tissues are made, one for each subtractive
primary, and layed one on top of the other. This process was
the standard one for photomechanical originals before being
displaced by the Dye Transfer process or direct photographs
of Kodachrome originals. It fell out of use in the 1940's
but was still in some use in the 1950's. Dye transfer was
much easier to handle and resulted in better reproduction.
Carbon prints are very permanent since they use pigments
rather than dyes, and Dye Transfer prints also have long
lives since the dyes used can be chosen to be long life
types.
  The books refered to in my last post, especially the
Friedman book, cover both processes thoroughly. Technicolor
discontinued the process for motion picture printing because
it had become uneconomical. They had only one plant for
making the prints: it was getting old and was being pushed
to higher speeds than it could handle. Technicolor has built
a new pilot plant and found a dye set that is relativly
environmentally acceptable. Dye transfer is very economical
where very large numbers of prints are made. When it was
discontinued the price break was about 200 prints but most
theatrical motion pictures were printed in only about that
number. Currently, most movies are released in a couple of
thousand theaters at once. At this rate the dye transfer
process becomes significantly cheaper than chromogenic print
film.

---
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com