Three related looks that all treat the picture as a carved surface lit from an angle: Bas Relief, Plaster, and Note Paper.
The picture is blurred, brightness is read as height, and the slope at each point decides whether it catches the light or falls into shadow.
The modes differ in what they do to the height before lighting it. Bas Relief lights it as it is, giving a shallow carving. Plaster flattens it into plateaus with steep sides first and inverts it, so dark areas rise, then makes the shading glossy, which is what gives it the look of moulded plaster. Note Paper cuts the height into a hard two-tone shape, adds a beveled band along the boundary, and sprinkles grain across the result, so it reads as torn and pressed paper.
smoothness sets the blur, and so how coarse the shapes the carving follows are.