WHYY’s new weekly arts show On Canvas, which premieres tonight on its digital arts channel, is “just the kind of thing the big public station in the nation’s fourth-largest TV market should be doing: a showcase of the variety of performing arts in the region,” writes Philadelphia Inquirer TV critic Jonathan Storm. He lauds the program for not crowding performances–a banjo gathering, classical Arab music, a Native American flute player, a local singer-songwriter–with interviews and explanation.