Mostly unknown to comics readers during his career—uncredited on "Batman" and "Superman", Sprang placed his name only on a handful of other stories that he drew, such as in "Real Fact Comics"—Sprang began to receive notice from comics fandom in the 1970s, when he became a regular attendee at comic conventions and later began drawing and selling reproductions of his Golden Age comics covers. During the 1980s (c. 1984–87) he devoted some of his time to recreating comic book material for the burgeoning collector's market, before returning to comics in 1987 for "occasional assignments". In 1990, he did the covers for "Detective Comics" #622–624. In 1995 and 1996, he produced two limited-edition lithographs depicting the Batcave ("Secrets of the Batcave") and the Batman cast of characters ("Guardians of Gotham City").