How hand-painted signs have persisted in Chicago

Dan Kamba and Chuck Wilmarth are debating how to spell Oscar Mayer wiener.

The "i" should be before the "e," says Kamba, co-owner of Southwest Signs in the Clearing neighborhood, but Wilmarth, the other co-owner and Kamba's brother-in-law, wants to be sure. Brush in hand and bent over a 4-by-8-foot...