These were some really fast sketches I did this morning but they turned out nice. The original drawings were A1 pen on plain white paper then I snapped a picture of them took them into Photoshop desaturated, inverted and adjusted them to come out like this. Very quickly thinking in the negative is great fun, when shading becomes lighting the tables are turned. It's interesting to play with line weight too. Just thought I would put it out there and recommend you try it if you haven't already but don't cheat and draw in white on black paper, the experience is completely different.