Look upwards in an open field and your view drifts quickly free, from bush to track, to open collision with the vast, concave sky. Look upwards in a city and any path to sky is mediated by the facades of buildings, by house fronts or apartment blocks, capped off by those last perches for eyes: rooftops. Above our heads, ever bared to the sky, the roofscape is the major subject of Hendrik Kolenberg’s latest solo exhibition Shaped by light. An abstractionist on foot, or a “shape man” by his own telling, Kolenberg finds his subjects over the course of repeated walks through a city’s centre, its outskirts and suburbs. There he seeks those forms, born of the interplay of light and urban object, which are capable of staying. This exhibition takes us through the streets of Rotterdam, the city of his birth, and Sydney, where he lives; these two cities are closest to him, yet are here seen through an eye ever drawn to those places left to the edge of gaze. The roof-dwellers in works like Double-dekker, Rotterdam and Roof sculpture, Eastwood are unlikely to have been installed with artistic contemplation in mind. The rooftop of an inner-city building is a place where the demands of…