People behind the windows of public buses — at the end of a working day in the centre of Paris, they wait for the bus to bring them back to the banlieue. They seem introspective, engrossed in thought, their gaze directed towards an inner landscape. The camera’s view of the subjects it portrays is frequently refracted by mirrorings and iridescent light reflections. As a counterpoint to these photographs are the ephemeral traces of human presence; scratches scored into the glass, fingerprints, and other deposits left on the bus windows. In these pictures – created by collaborative duo Martin Keller and Dagmar Wittwer – they come across as abstract gestures of the light, cloud formations, or clusters of stars. It is as if the viewer is looking into an incubator in which the matrix of human existence is assembling itself from tiny particles. Point de Depart, which follows the duo's celebrated book Passengers, has been produced with the generous support of the Swiss Arts Council Pro Helvetia.