Who were the main figures involved in the introduction in 1892 of 35 mm film for still photography and motion pictures?

Question

The standard negative pulldown for 35 mm motion picture film is four perforations per frame along both edges, which makes for exactly how many frames per foot?

Answer 1

William Dickson, Thomas Edison & George Eastman
The standard introduced in 1892 is relatively unchanged since then. Its longevity is largely because the ubiquity of 35 mm movie projectors in commercial movie theatres makes it the only motion picture format, film or video, which can be played in almost any cinema in the world.