For actress, play is a study in opposites BY MARTIN F. KOHN
Yet another example of why they call it acting:<br /> In "Hairspray," Linda Hart plays Velma Von Tussle, a TV producer dead set against letting black kids on the all-white afternoon dance show in 1962. In real life, Hart spent her childhood years in Detroit, where her father, the Rev. Ralph Hart, was (and is) the white pastor of a predominantly black church.