sometimes taking just one channel works fine too. You can take the R, G, B, C, M, Y, K, H, S, or L, channel as bumpmap. Often one of them will be good enough. It saves you the time of making your own bumpmap. But ofcoarse making your own special bumpmap works best.

(_/)
(='.'=)
(")(")This is Bunny. Copy and paste bunny into your signature to help him gain world domination.