We walked through a room with a ceiling that went up and up, between rows of photographs, both colour and black-and-white. And not just in, but of: black people and white people photographed on different film stocks. And not just that endlessly reductive duality, but every imaginable variation of skin was sampled here. It was actual film—I knew, because I could see the negatives hanging in spirals by the side of each board—and the textures and tones of the skin were rendered to different degrees of fidelity and atmosphere. In one photograph, a tall fellow I judged to be Haitian looked sickly and angry. In another, he seemed filled with a secret life. Next to him was a pale woman with a French flag on her shoulder, a UN official, glowering hot and rashy in the second photograph, filled with a sort of diffident hope in the first. It was the same all the way along the rows: pairs and sometimes sequences of images with different subjects, and always one set favoured one kind of skin and made others look oddly sinister. Then there were streets done the same way, hazy and soft, hard and cold, warm and welcoming, and on and on, all in monochrome, all subtly different and yet showing the same scene at the same time. Different countries, different architectures. Different worlds.