A great mural is a ready-made set, but a photograph of the wall alone is a photograph of someone else's art. The picture is what happens when a person enters it — completing the scene, contrasting with it, or unknowingly echoing it.

The method: find a strong piece of street art with good light, set your frame, and fish — wait for the right subject to walk through. Match or clash the colours, or catch a pose that answers the painting.

Look for: a passer-by whose clothing, gesture or expression plays off the art behind them. The wall is the stage; the person is the picture.