Contributed by Jonathan Stevenson / “Out of the Blue” at Frosch & Co boasts a tight concept and adds real snap to the conversation presumed suspended until after Labor Day. The idea is to explore how the color blue ramifies through the lenses of different painters. That might seem like a merely modular survey, since other colors too have distinct connotations. But blue’s, as the gallery’s press statement notes, seem to swing more dramatically – between cool and warm, masculine and feminine, obscene and pure, barbaric and royal, stormy and serene. This quality makes for an unusually rich array.