[eric nixon]

Generally bump map power should be really low, excessive darkening is usually a sign that the bump value is to high. I use values like 0.1 - 5.0 most of the time, (for maps with healthy contrast). It also depends how fine the bump detail is.

[joaomourao]

regarding bump mapping...
is there a relation between the bump value and real measurements? any chart? same thing for normal maps...
it would make sense... some say they use 1 to 5, others 1 to 50!?!?!?
cheers!

[Bubbaloo]

It depends on the contrast of the bump map, and scale/tiling of UV's.

[eric nixon]

Well said