September of 1976 revealed the Gemini Man television series. It was the second stab by NBC at the 'invisible man' concept, as the television season before, they broadcast The Invisible Man -- a series which barely made it to the half season mark.
I was one of those viewers who made a point to tune in week after week to catch the limited-time, in more ways than one, adventures of secret agent Gemini man Sam Casey (played by Ben Murphy). Casey could nip out of the visible light spectrum, but for only 15 minutes in total per day -- or he would perish.
Capping the amount of time the show's protagonist could cloak to invisibility definitely made plotting and jeopardy more interesting, but once the network realized Sam Casey wasn't making television ratings more visible, the series disappeared forever -- after just half a dozen episodes.
But I enjoyed it.