Anisotropy is why flat metal is not flat

The record column was first shaded the way the plaster is — Lambert against the key light — and came out as white wax. Metal has no diffuse term at all: its colour is the room, reflected, and the difference between a mirror and satin is only how blurred that reflection is.

With no environment map in the project, both the column and the chrome mark reflect a function instead: a dark floor, a bright horizon, a mid ceiling. That gets you most of the way, and then the bands have to be fitted to the sweep the surface actually has. A vertical face two units from the axis, seen from ten, sweeps its reflected direction over about a quarter of a radian — ranges written for the whole hemisphere put the entire face inside one band, which is a second way to arrive at a flat white sheet.

The last piece is the grain. Real brushing at this distance is finer than the pixels showing it, and grain finer than its pixels is not subtle, it is moiré. The correct rendering of sub-pixel grain is a wider specular lobe, not a stripe: keep the visible bands few and put the fine part in the highlight.