Hello Elkanj. What I do is to position a jpeg on the Background Layer, turn off the Greyscale/Colour mode and experiment with a very Pale blue or green, so that all the outlines can be seen, and then lock the layer. Then trace on an above layer(Standard), my experience is that the tracing proceedure gets very jumpy especially when working with photos, and not so much with scanned lined drawings. Good Luck Stephen
