[pure-silver] Re: Kodachrome
----- Original Message ----- From: "Mark Blackwell" <mblackwell1958@xxxxxxxxx> 
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Monday, February 25, 2008 8:43 AM
Subject: [pure-silver] Re: Kodachrome



Ok I am old but I still remember the old song
"Please don't take my Kodachrome away." Well I figured that would never happen, but it may not be long. 

Richard Knoppow <dickburk@xxxxxxxxxxxxx> wrote:
----- Original Message ----- From: "Dave James" 
To:

Sent: Monday, February 25, 2008 5:49 AM
Subject: [pure-silver] Re: Kodachrome



Clarence Rhymer  wrote:
   Of course there is always Dwayne's if you want colour.
Unfortunately, Dwayne's no longer processes Kodachrome
120. AFAIK, no one does.


   The last time Kodak upgraded the processing machines
they discontinued 120. 35mm is the only still film size that 
can processed now. I am not sure of the status of motion
picture film, I think its possible the Swiss lab still does 
Super-8.

---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
Well, from other posts I guess the Swiss lab doesn't exist. Kodak has been trying to discontinue Kodachrome for a very long time now. It has certain unique features which give it a body of loyal users but its evidently not profitable to make and is difficult to process. Its main virtue seems to be very long dark storage life. At one time Kodachrome simply looked better than any other color film but I think that hasn't been true for years now. Kodachrome has a curious history. George Eastman evidently became interested in an easy to use color film for amateurs as early as 1900. Its been suggested that one reason he brought Kenneth Mees to the US to form the research labs was to devise a practical color film. The labs tried at least two forms of color before going to a multi-layer film. The earliest was also called Kodacolor and was of the colored reseau type similar to Duffay Color, Finely Color, and Autocolor, there were others of this type. I think this product was confined to the 1920s or even before. The second type of color film and one specifically intended for home movie use was the first Kodachrome. This was a lenticular type film, a reversal B&W film making use of a striped color filter over the camera lens and a similar filter on the projection lens. Lenticular films have problems with fringing of moving objects and are extremely difficult to duplicate. For a time in the mid 1930's Kodak was carrying on research in co-operation with Paramount Pictures on a lenticular system suitable for theatrical motion pictures. It was not successful. Both of these products were discontinued. Kodak could not solve the problem of how to prevent dyes from migrating between layers of multi-layer film. They eventually wound up by leaving the dye formers (couplers) out of the three emulsions altogether and relying on a complex processing method to generate the dyes in the appropriate layers. This film was also called Kodachrome and was he first version of the current product. Partially because of the very complex process Kodachrome was made only as 16mm motion picture film. It was released in 1935. A couple of years later a modified and somewhat simplified processing method was devised which allowed other sizes to be handled and Kodachrome became available in 35mm, roll film sizes, and sheet film up to 11x14. These were available until the development of Ektachrome c.1946 at which time the sheet sizes were discontinued. Agfa had solved the problem of sequestering the dyes that plagued Kodak at about the same time as Kodak released Kodachrome. Agfa called its film Agfacolor and both negative and transparency films were made but not sold outside of Germany. Agfa's technique was to attach the dyes to very long chain molecules which could not migrate in the supporting gelatin. Eventually Kodak came up with an alternative method of anchoring the dyes, a method of encapsulating them in a resin which was permiable by the processing chemicals but not by the dye molecules. This method was first used in a negative film called Kodacolor. A similar material but coated on paper was used to print the negatives. The early form of Kodacolor did not have integral color masking so left something to be desired in color quality but nonetheless made color available to the snap-shooter (c.1940). During WW-2 Kodak made a great deal of color aerial film. I think the trade name Ektachrome or perhaps Ektacolor was used for these. There is a rumor that Kodak made use of Agfa patents for this film since these patents were in the hands of the U.S. Government but this may not be true because the Kodacolor method of anchoring dyes had been developed by this time. One advantage of the Ektacolor and Ektachrome type films was that they could be processed by the end user, a necessity for war time materials. Once the war was over Kodak released Ektachrome (transparency film) to the market in sheet sizes and at the same time discontinued Kodachrome in sheet sizes. I think Kodak intended to discontinue Kodachrome altogether at this time but Kodachrome was noticeably superior to Ektachrome so they never managed it. I am not sure of which method of manufacture survives now but think it is the Kodak method of using resin encapsulation. The fact that Kodachrome has survived for seventy-three years says something about the loyalty of its users especially because it was after all a stop-gap makeshift although an elegant one at that. 

---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx 
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