Color film? I didn't know they even made color film 40 years ago.

Sorry, I forgot to put the irony indicator into my post: irony or ;-)

But while I'm mentioning it, most color films of the 1950-60s (except
Kodachrome of course) were much less archival than those of today.

G- Blank axed:

I once left an exposed roll of Supra 800 for just one year, and
the images printed from it were totally unacceptable.

You made the blanket statement. The next question is what did the
negative look like? I have kept slide films up to a year with no
adverse affects, it may depend on where one stores the film.

The negatives were awful as well, judging by HP Photosmart scans.
I'm telling ya, "Process Promptly" like it says on the box.