In the Sandra Feinstein-Gamm Theatre’s latest production, “Red,” it’s the late 1950s and abstract-expressionist painter Mark Rothko is about to take on his greatest challenge. Audience members will explore the emotional palette of the real-life 20th-century artist as he works to create his definitive dark red and black murals for the Four Seasons restaurant on New York City’s Park Avenue. The show will feature Fred Sullivan Jr. as Rothko during his debut on The Gamm’s stage.