We all love the ghostly remnants of old painted signs around the neighborhood, but nowadays it’s easier to hang up a printed banner. So that makes the hand-painted signage on the side of 528 Canal even more of a treat. I love watching the ad take shape over the course of days, such as the new one for Perrier. Enjoy it while it lasts: The building is slated to come down at some point, when a single-family home will be built on that lot and the adjacent vacant one.