From left: James Hayden Rodriguez (Ken) and Rob Nagle (Rothko) in "Red" at Laguna Playhouse (Photo by Jason Niedle) What do artists talk about when they talk about art? That is the subject of John Logan’s play “Red,” assuredly directed by J. Scott Lapp at the Laguna Playhouse through June 28. Specifically, middle-aged artist Mark Rothko (Rob Nagle) talks to his young assistant Ken (James Hayden Rodriguez) about art (mostly his own), philosophy, myth and the color red. The fir