Kodak Kodachrome-X

Kodachrome-X arrived in 1962, a year after Kodachrome II, as Kodak's faster slide film for photographers who wanted Kodachrome color rendering at speeds usable indoors and in lower outdoor light. The base sensitivity was ASA 64, roughly a stop and a third faster than Kodachrome II, which meant handheld shooting at street apertures instead of the tripod work Kodachrome II generally required. Processing was the same K-12 chemistry. The dyes were added during development rather than baked into the emulsion, which is the structural reason Kodachrome slides from this era still hold color decades later.

In 1974 Kodak moved both Kodachrome II and Kodachrome-X to the new K-14 process and rebranded them as Kodachrome 25 and Kodachrome 64. Kodachrome 64 inherited the 64 speed point and ran until Kodak announced final production in June 2009. Dwayne's Photo in Parsons, Kansas processed the last roll in December 2010. That was the end of K-14 service worldwide.

The character carried forward: warm reds, restrained blues, a particular rendering of green foliage that does not quite match anything in E-6. Steve McCurry shot the bulk of his National Geographic work on the K-14 successor and described the color as poetic in interviews around the 2010 wind-down. The Kodachrome-X emulsion was the direct ancestor.

Format support was 35mm, 126 cartridge, and 110 cartridge, which placed the film in the Instamatic camera ecosystem that dominated consumer photography through the sixties and seventies. There was no medium format Kodachrome-X. Surviving rolls cannot be processed in color anywhere: K-12 chemistry is gone and the dye couplers it required have no modern substitute.

Reciprocity exponent is 1.10. Zone Light Meter applies the correction past one second on the standard curve, which puts a 30-second meter reading at about 35 seconds at the negative. For the original users, on handheld outdoor work at ASA 64, that threshold rarely came up. For anyone holding a freezer roll today, the question is academic.