PE and Holmburgers (Where did you get that name?),
Please excuse my uncharacteristic optimism. It must be the painkillers! But,PE, I was not referring only to patents and publications. I was referring to internal records which would never be disclosed,accept if nobody cared. I am sure that a company like EK would have internal documents for every aspect of every process. They would leave nothing to the skill of any individual. The records must exist. Autochrome, on the other hand, probably did rely on the expertise of individuals. That was a different time.
As for the the degree of interest in one process or another, you may be gauging your estimates on numbers,rather than intensity on the part of a few people.