Pro color transparency films (that's what the P in PKR means) are allowed to age while being tested from time to time until the colors meet the designed target, then tested for actual speed, then refrigerated. It might be marked a nominal ISO 64 but it'll tell you if it's really ISO 50, 64, or 80, or at least that's how it used to be. Unless you're shooting under controlled lighting conditions (studio strobes) or have your meter calibrated and all your shutter speeds adjusted closer than just "within tolerences" you're wasting your money on the pro film. There should be no difference in sharpness. NONE!''
In a way Kodachrome is a dye transfer, except the dye isn't transferred anyplace. But Kodachrome is a pure dye image, not a "dye-coupled image". There is no silver left in the processed film, unlike color negative and Ektachrome/Fujichrome type slide films where the silver is used as a coupler for the dyes.
Kodachrome is a complicated process where each of the three color layers is processed, re-exposed, bleached and dyed seperately. All that remains in the film are the three layers of dye. If anybody can explain it better, then go for it!
The dyes are transparent compared to the silver in a dye coupled film, but their is some residual appearance of granularity because the dyes are taking the place of what was a silver image, but it's barely noticeable. The dyes can be chosen for stability rather than their ability to couple with silver. For long term dark storage nothing beats Kodachrome for holding its color, but in the light, such as frequently projecting your slides, Ektachrome or positive movie release prints from a color negative holds up better at the expense of long term color stability.
