Although the White and Black Paintings qualify as monochromes, in other respects they are opposed. Applied with rollers on panels, the Whites have little inflection, and Rauschenberg said they could be repainted, even remade (as some were in 1965 and 1968), while the Blacks have almost too much texture: built up of newspaper strips dipped in paint, glued to canvas, then coated with more paint, they appear worn and fragile, and some show a range of colour and tone too. The Whites appear pristine, empty, flat and serial; the Blacks look rough, full, encrusted and singular. This makes the Whites seem porous to the world and the Blacks closed to it, which is largely how they were received. In keeping with his own desire to suppress authorship and to invite indeterminacy, John Cage called the White Paintings ‘airports’ for ambient accidents of light, shadow and dust. ‘If one were sensitive enough that you could read [them],’ Rauschenberg added, ‘you would know how many people were in the room, what time it was, and what the weather was like outside.’ For their part the Black Paintings insist on objecthood in ways that go beyond ravaged surfaces; tacked directly to supports, they were presented without frames, and Rauschenberg often photographed them among everyday things. As the curator Walter Hopps commented, they also underscore ‘the fact of a new urban surface’.