it was done with Photoshop just to prove a point: i suck at digital sketching. for years i favoured Photoshop for quick sketches (like the first years of Scary Boy, all done that way) and more elaborate pieces. but now it always feels like something's missing.
when i sketch on paper it looks and feels better. i know some artists don't seem to have this problem, seeing how they sketch effortlessly on Photoshop.
maybe i don't have the right brushes, or the right method but it takes me longer to do a decent digital sketch than what it takes me to do it on a notepad or a piece of paper with a pen... any pen.
still, photoshop (or painter, etc) is cool for so many other things. it allows unlimited scope for experimentation. and for colouring it beats conventional techniques.