Manufactured by Kodak from 1935 to 2009, Kodachrome was the first commercially successful color film and was used to capture some of the most iconic images of the late 20th century. The film was known for its stability—if stored properly, it could be developed decades after being exposed and would retain its color and density for decades. Yet, advances in digital photography and the development of competing films considerably reduced demand. What famous images were recorded on Kodachrome? More… Discuss
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Processing of Kodachrome films
Kodachrome required complex processing that could not practicably be carried out by amateurs. The process has undergone four significant alterations since its inception. The final version of the process, designated K-14, was introduced in 1974. The process was complex and exacting, requiring technicians with extensive chemistry training, as well as large, difficult-to-operate machinery.
First, the antihalation backing was removed with an alkaline solution and wash. The film was developed using a developer containing phenidone and hydroquinone, which formed three superimposed negative images, one for each primary color.
After washing out the first developer, the film underwent re-exposure and redevelopment stages. Re-exposure exposed the silver halides that were not developed in the first developer, effectively fogging them. A color developer then developed the fogged image, and exhaustion products formed a dye in the color complementary to the layer’s sensitivity. The red-sensitive layer was re-exposed through the base of the film with red light, and then redeveloped forming cyan dye. The blue-sensitive layer was re-exposed through the emulsion side of the film with blue light, and then redeveloped with a developer to form yellow dye. The green-sensitive layer was redeveloped with a developer that chemically fogged it and formed magenta dye. The two light re-exposures had to be carefully controlled so as not to cause re-exposure of the green-sensitive layer.
Following color development, the metallic silver was converted back to silver halide using a bleach solution. The film was then fixed, making these silver halides soluble and leaving only the final dye image. The film was finally washed to remove residual chemicals which might have caused deterioration of the dye image, dried and cut.[27