I notice that all gradations, not just linear, show a regular banding pattern. In a linear transparency, I notice wide bands about 1/2" wide, with maybe 17 very small bands making up each of the wider ones. This banding would be difficult to get rid of by blurring in another program. By the time the fill was sufficiently evened by blurring, the edges'd be bad.

I want to use a Xara drawing as a heightfield model in a terrain application. These greyscale translations are very sensitive to even slight variations in shades, so that banding sure does show up in 3D the model.