Northside’s Thunder-Sky, Inc. wrestles with the term “outsider” art. Though it’s a marketable label, it can heap sometimes-false assumptions upon artists. They’re presumed to be uneducated, untrained, isolated, developmentally disabled and/or indifferent to profit. Thunder-Sky, Inc. co-founders Keith Banner and Bill Ross prefer “unconventional” to describe the works. But an appetite for definitive labels persists. […]