A crop of painting-focused group shows has sprouted in the West Loop this summer. While you'll find some appealing works in all of them, we're partial to Pop Sizzle Hum at Tony Wight, featuring Judy Ledgerwood, Steven Husby, Carrie Gundersdorf, and Pamela Fraser. If the show is on the slender side, with three of the four artists represented by single paintings, that quality is largely a virtue. Effective in its economy, the exhibition is like a pithy conversation about approaches to abstraction, rather than the usual theme party where everyone arrives in similar outfits and jockeys for control of the music. Adding to the discussion is the concurrent exhibition Single Channels, an enjoyable sequence of animated videos.