If you're rendering using gamma correction at 2.2 (the default) save your scene first and then go to the drop down menu Scripts - Material Mods - Change Gamma.  Enter a value of 1, Select "all props and figures" hit OK, select "all of the above" and OK once again.   Be careful not to select all materials because you only want a gamma of 1 on transparencies, bumps, and displacements and this scripts does it all much more quickly than doing it manually in the material room.