It is simple actually.

All color maps need to be loaded with Gamma set at 2.2, or use Render Gamma settings when you render at gamma 2.2 (what you always should do)

All Black and White maps that drive transparancy, bump or displacement should be loaded at Gamma 1.

Poser 1, 2, 3, 4, 5, 7, P8 and PPro2010, P9 and PP2012, P10 and PP2014 Game Dev
"Do not drive faster then your angel can fly"!