Use Line for the Shape and 30 lines/inch for the frequency. Step 5 Undo some of the steps until you get the greyscale image. Turn off the visibility of all layers with the exception of the next Threshold layer. Repeat the process of increasing the line weight by 1pt then pasting the heavier version on a new layer. Do this for 3pt, 4pt, 5pt and finally 6pt lines. Now comes the trick that really allows this technique to work.