My 'photoshop' magic is limited to inverting colours in order to make the negative image. More a matter of pushing a button than one of skill. :D I just put on a whole lot of paint to get a thick tone and told the scanner to do a lot of colour saturation on scanning. Even then it's mostly knowing what you're doing on the paper in terms of colour and line density. (I'm not sure if I know what I'm doing, mind you..)
My 'photoshop' magic is limited to inverting colours in order to make the negative image. More a mat