Bill P wrote:
My experience with fading is against yours. I have Kodachromes from the 70's that look pristine, and other that look like an old Ektachrome. And I have ektachromes from the same time that are pristine and others that aren't. I have Agfachromes, a great landscape film, that have turned almost clear and others that are perfect. As to Ansco, i never has one that would last out the month.
I'm convinced it's all process-dependent. Kodachrome was a rigidly controlled process. It was very consistent, and there were just a handful of labs qualified to do it. Most Kodachromes since the 1930s are in decent shape, if kept under controlled conditions (room temperature range, 50% relative humidity, in trays or archival boxes or sleeves).
But Ektachrome? Well... E6 was done everywhere. I souped thousands of rolls of it myself, back in the 1980s, in a deep tank sink line process with temperature control and Nitrogen burst agitation. We used Kodak E6 chemistry, which was an eight step process:
First Developer
Reversal Bath
Wash
Color Developer
Bleach
Fix
Wash
Stabilizer
That last step was pretty critical! Unfortunately, for a long time, it was formaldehyde-based. At some point, formaldehyde made its way onto a hazardous substance list, so Kodak changed it.
Many labs left out the stabilizer. They got tired of contact dermatitis and other bad things happening to lab workers. It was also an expense many labs felt they could eliminate. I wore gloves, and the stabilizer still made my skin peel.
Despite following Kodak's instructions to the letter, nearly all my Ektachrome slides from 1979 to 1988 are cyan-blue. So are Ektachromes from the late 1960s processed by Kodak in Atlanta.
Several other companies made/make E6 compatible kits. Who knows what is in them. I used one that was just four solutions. The colors came out very weird.
Anscochrome? I dunno. I have some from the early 1950s that are excellent. They are in Ansco mounts, so probably were processed properly. My uncle liked that film. Slides of me at age 2 were made with it. They're decent.