Thursday, December 30, 2010
Types of Film: Kodachrome
Today is the last day that Kodak Kodachrome film will be developed. Dwayne's Photo in Kansas is the last place that develops the film in the way it was supposed to be developed and that will cease today when Dwayne develops the last roll before selling the machines for scrap. So, I decided, after several friends asked me what Kodachrome was and what the difference is between Kodachrome, E-6, C-41, etc. film, that I would take some time and write about each different type of film. Not just for those who were asking, but also because, being someone who quite likes history I thought it would be interesting to delve into the history of different films and their development.
So, with the demise of Kodachrome I thought I would start with...Kodachrome.
Kodachrome was created in the early 1930's by two musicians named Leopold Godowsky, Jr. and Leopold Mannes and manufactured by Eastman Kodak. It's life span ran from 1935 until 2009 when Kodak discontinued the manufacture of the film. It was possible to get the film developed until today, December 30th, 2010, but only at one place in the world, Dwayne's Photo in Kansas. Kodachrome had a number of ISO's that were discontinued in the following years: 2002 (ISO 25), 2005 (ISO 40 [8mm]), 2007 (ISO 200) and 2009 (ISO 64). There were quite a few formats available for the film as well: 16mm, 8mm, Super 8, 35mm movie, 35mm still, 120, 110, 126, 828 and 5"x4".
Kodachrome was a K-14 processed, color-reversal slide film (a type of film that produces a positive image on a transparent base) that had undergone 4 different alterations since it's introduction. The final, K-14 version was introduced in 1974; it was a complex system that required not only those specially trained with the chemicals, but also required the use of large and bulky machinery.
Why was it so difficult to develop Kodachrome? Well, Kodachrome film had no color dye couplers and as such the dyes were added during the processing in a separate step. Due to the decline in the need for the chemicals, they were all discontinued. Before getting into the short break-down of how the film is developed, let me point out the layers of the film, top to bottom: Blue sensitive (yellow), yellow filter, blue-green sensitive (magenta), blue-red sensitive (cyan), acetate base, rem-jet antihalation backing (as far as I can tell, this is a layer included to keep light from reflecting off the pressure plate of whatever else is behind the film; it ends up being washed away or turned transparent during processing). So...now on to the process of developing the film.
First the backing is removed. Then the first developer is applied, which causes all the exposed silver halide crystals to develop to a metallic silver. The yellow filter layer remains opaque due to its emulsion combination. The film is then washed before red light is re-exposed through the base which allows the remaining silver halide in the cyan layers to become developable. Now the Cyan developer can be added which contains a color developer and a cyan coupler which is colorless. After the color develops the silver, the developer, which has oxidized, reacts with the cyan coupler and forms a cyan dye. The film is then washed again before the blue-light re-exposure from the top which allows the undeveloped grains in the blue-sensitive layer (yellow) to become developable. The yellow filter layer, now opaque, keeps blue light from exposing the magenta. Then the yellow developer is added before another wash which is followed by the magenta developer. See? This is a lot and I'm not even done yet. Now, the magenta developer contains a chemical fogging agent that makes all the remaining undeveloped silver developable, then it's washed again. Then the film is conditioned with a conditioner which prepares the metallic silver for the bleach step, which oxidizes the metallic silver to silver halide. Finally, fixer is added before the film is washed a final time, rinsed and allowed to dry.
Yeesh! What a process! But, it was all worth it in the end because Kodachrome is well-liked for its amazing color-capturing ability and its dark-storage longevity. However, it is inferior to the E-6 process when used in slide projection.
Another part of Kodachrome's demise was the emergence of other films like Fuji's Fujichrome and Kodak's own Ektachrome which was less complex and faster to develop. I've never personally owned any Kodachrome, but I have dealt with (not developed on my own) both Ektachrome (which I had made into slides and also cross-processed with C-41 chemicals, on several different occasions) and Fuji's Velvia (which creates some beautiful, killer cross-processed images). It's sad to see a product of American history laid to rest after almost 3/4 of a century, but at least we have some of the most beautiful, colorful images that will last a long time. Oh, you can still get Kodachrome developed at some place called Film Rescue, but it's black and white only and it's quite expensive.
I gathered my information for this post from a PDF from Kodak on the processing of Kodachrome, as well as wikipedia (http://en.wikipedia.org/wiki/kodachrome) and Kodak's website.