A Key to Time — Don Howard

Alan Deacon, a graphic artist takes a contract to restore and print some old, damaged photos, and becomes entranced by a photo of a beautiful young woman. He finds a key in his bedroom after dreaming about her, and later discovers that they key opens a door to the 1950s, where he meets the woman and becomes infatuated with her. He also has a sweetheart in the present, and is torn between the two women Unfortunately, the chief of police back in the 50s also has his eye on the young woman, and he causes no end of trouble for the couple, which ultimately results in tragedy.
Alan learns through experience that he can't permanently live out of his time,
but uses the "key to time" to wreak revenge on the corrupt police chief.