[AgX]

Until 1965, when the new Ektaprint 3 process and papers and the new C41 process, all other companies had their own proprietary processes.

Process Ektaprint-3 was introduced 1971.
Process C-41 was introduced 1975.

Agfa, until about 1965 was using a different color chemistry...

Agfa was the last western company to change over to oil-embedded couplers (Ektachrome principle).
They started that change in 1978.