[1] Eastmancolor, introduced in 1950, was one of the first widely successful "single-strip colour" processes, and eventually displaced the more cumbersome Technicolor.
Later research enabled faster development and more environmentally friendly film and process (and thus quicker photo lab turnaround time).
The ECN-2 process has normally been reserved for high volume labs involving hundreds or thousands of feet of film in a linear processor.
One essential difference is the presence of an orange "mask" (i.e., effectively an orange base) on all films processed by Eastman Color Negative, and no "mask" (i.e., effectively a clear base) on all films processed by ECP.
Later research enabled faster development and more environmentally friendly film and process (and thus quicker photo lab turnaround time).