Over easter, I built a screen with some 1.3 gain material and I built a high shelf for my projector which I got at perfect right angles. Very square image - very happy with it in everyway, except (and I didn't notice this previously), I have severe banding in dark scenes. Most annoying. It only occurs in very dark scenes when there isn't much light shining at the screen, so I thought it might be something to do with my screen, I inspected it, and its flat and smooth. I don't know much about the infamous vertical banding, but I've not heard of it being exclusive to dark scenes before. What could this be, and more importantly how can I get rid? Also, am I alone in this observation?