The one specimen here that is not about colour. A brushed surface has its micro-scratches all running one way, so a highlight that would be a round spot on polished metal is drawn out into a streak along the grain and pinched across it — and that shape, not any hue, is how the eye identifies steel. The matte coat scatters the reflection rather than mirroring it, which is why the card shows itself instead of the room. The design is etched rather than printed: acid takes the metal away, and what you read is light caught on the walls of what is missing.