nomuse, I believe that the bump algorithm reads the luminence value and uses that as the key, so no, you wouldn't get any more levels of height. This is not true of HDRI though, and you can get an awful lot more levels of light using the HDR format than standard LDR (BMP,JPG, TIF)... [sorry for the OT non-sequiter, still working on the tuto for creating your own HDR's: It's tough making sure that you can duplicate your own work!]. Ken