What could the future possibly hold for an artist if they have grown too comfortable with success? If they have stayed put in that snug place of glory, but the times have moved on fast without them? These are the hefty considerations at the heart of “Paint,” a slight comedy that sadly embraces neither the worthwhile questions that surround its central premise nor the story’s dark humor potential.That’s too bad, because writer-director Brit McAdams’ narrative feature debut is rooted in a genuinely fascinating subject that apparently served as an inspiration for “Paint.” McAdam’s muse is Bob Ross, a real-life American public television mainstay of the ‘80s and ‘90s. Being the host of a successful PBS show called “The Joy of Painting” during that time, Ross built a loyal audience who loved and were mesmerized by his soothing voice, and even haunted by his creative process and ease with a brush, as Ross slowly created his art in front of curious eyes, narrating it softly and philosophically.