Sketch on canvas

So after many sketches on paper, I usually use pencil to start and then black marker to finalize the lines, it's time to transfer these to the canvas. Using a lamp behind the canvas and placing the individual sketches on the underside of the canvas, so the lines show through to the top, helps get the correct position and size. Once I have the lightly sketched pencil lines just as I want them, I again use marker so I can see the lines through the first stages of painting.