The late Robert Giard, a photographer and longtime Amagansett resident, began making portraits of gay and lesbian writers in 1985 after seeing “The Normal Heart,” Larry Kramer’s play about the AIDS crisis. By the end of the evening, he wrote in the introduction to a 1997 book in which a number of the photos were collected, he had decided that his work “should be of use to other gay people by recording something of note about our experience, our history, and our culture.”