My mother worked for a company called Victor Animatograph. She did the colorizing of b&w photos I thought. I guess they did films, too, wish I'd asked her more about it.
A lot were produced on linen-like paper. I scanned and shared a lot of mine but they are on an old hard drive somewhere or a backup Passport that failed.
There are a lot of videos of Czarist Russia on yt that have been colorized; I assumed by hand. They look like I would expect colorized of b&w to look whereas the video tonight I wasn't prepared for the high quality of the coloring.
Thak you for your info. I don't know what to think at this point. All my various experience and never enough.
As I was studying how they reproduced those color postcards.
Was amazed to learn that color photography went much further back that I would have guessed. The problem of course is they were not commercially practical until Kodachrome. Sadly Kodachrome is no longer made.