Ok, so here's my process for developing an approved cover sketch for the Uncanny X-Men 518 cover.
The first drawing is a 4x 5" sketch done in my sketchbook with blue pencil, and a black Pitt pen.
The second drawing is the cleaned up scan ( in Photoshop CS3 with a Wacom Tablet) that is then turned in a blue line drawing that I print out and
The third drawing is worked up over that blue line print out at the same 4 x 5" size
The fourth drawing is the scanned and cleaned (in PS) version
The final color sketch is the result of drawing and coloring in PS and getting the cover proportions dead on. This is the version that is sent off to Marvel for approval. You can see how it turned out from there below!