Starting with a blank canvas 800 x 600:   1.  Create new layer   2. Cast a rectangular selection the full width of the canvas and approx 90pixels high.  Roughly center it vertically.   3. Drag out a linear gradient within the selection.  Dark side on the right, light on the left.   4. Effects > Render > Clouds over the selection with settings  51 | 0.5 | Color Burn.   5. Blur the selection using Motion Blur with settings 0 and distance =50.   6. Run Black and Alpha+ over the se