The Ars Electronica riverfront

The Ars Electronica Center sits on the northern bank of the Danube at the foot of the Nibelungenbrücke, and its outer skin is made of some forty thousand LEDs behind glass. From dusk the whole building shifts colour slowly across its full height, and the river doubles it — which is why this is the picture that says Linz to anyone who has been there.

The frame is taken from the bridge or from the opposite bank, where the Lentos art museum stands with its own lit glass façade a few hundred metres downstream. The two together, with the Danube between them, give a foreground of water, two coloured buildings and the dark hill of the Pöstlingberg above with the basilica picked out in light.

This is a blue-hour subject and the window is short — about twenty-five minutes after sunset, when the sky still holds colour and the façade is already on. Full dark loses the sky and the building's colour blows out against it. In summer that means waiting until nearly ten; in December it comes shortly after four.

Daylight is a different building — plain glass, a broad promenade along the Donaulände with lawns and benches, and the bridge as a hard geometric backdrop. Both work; they are not the same location. Programme and lighting change through the year, and the façade is dark on some nights, so check before planning around it.