U of S | Mailing List Archive | alt-photo-process-l | Re: 3 questions (one of them dumb)

Re: 3 questions (one of them dumb)

----- Original Message ----- From: "Diana Bloomfield" <dhbloomfield@bellsouth.net>
To: <alt-photo-process-l@usask.ca>
Sent: Sunday, November 16, 2008 9:16 PM
Subject: Re: 3 questions (one of them dumb)

I always understood chromogenic prints to be those prints specifically made from color negatives (as opposed to prints made from color positives . . . or Polaroids? . . . or from a digital file?). I'm surprised, though, to read that calling a chromogenic print a c-print, is "improper." Did I read that right? I always thought a chromogenic print and a c-print were the exact same thing. If not, I've sure been labeling my work incorrectly for a number of years now.

Over the summer, I saw the alt process show at Tilt Gallery in Phoenix, and there was also a c-print included in that show. Although the print was wonderful, I was very surprised to see that a c-print was considered "alternative." I would have thought a straight b&w silver print to be a whole lot more "alternative" at this point, than a c-print. Is it really that unusual for someone to be making a print from a color negative these days?

Chromogenic refers to any print, negative or reversal (the print I mean) made using a process which generates dyes in the emulsion. All modern materials have "couplers" in the emulsion which reacts with substances generated in the process of development to to produce the appropriate dyes. Kodachrome does not contain couplers in the emulsion, rather they are in the reversal developers. The Kodachrome process is such as to separate the development of the three color layers so that the appropriate dye is generated in each. It is still a chromogenic process because the dye is created in the emulsion by the development process. Kodak resorted to using the rather elaborate Kodachrome development process because, at the time, they were in a rush to get a color film on the market and could not figure out a method of preventing the couplers and resultant dyes from wandering around in the emulsion layers or between layers. AGFA beat them to the punch with this but Kodak eventually came up with an alternative method as was used in Kodacolor and later Kodak color films.
Chromogenic films or prints can be either positive-negative or reversal, the principle of generating the dye as a part of the development process is the same although accomplished at different steps in the processing. Prints made by the Cibachrome/Ilfochrome process, which is a reversal process, are not chromogenic. The dyes exist in the emulsion and are destroyed rather than being generated, by the development process. Processes where the color is applied to the print such as dye-transfer or color carbon are not chromogenic.
Type C is old Kodak terminology for a chromogenic print made from a negative, Type-R was the equivalent reversal print. The terms got to be well understood and persist even though they are pretty old.

Richard Knoppow
Los Angeles, CA, USA