There's a script to do it for you. Find on the menu bar under Scripts>Material Mods>changeGamma

You need to change the gamma settings on transparencies, bump, and displacement maps to 1.

I found I sometimes had to run this several times to get it work. Don't know why.

The best way to deal with this issue is to download Snarlygribbly's "scenefixer" (Google for it, and you will find it).

I think this version should work: 

http://snarlygribbly.org/3d/forum/viewtopic.php?f=8&t=13&sid=7319ddc3a0f6c477a3f6caa296586195

It has an interface that will do the entire scene, or just a single prop or figure that you've selected. If you download it (and you should: it's a fantastic utility that does other very useful things), select a prop or figure, run the utility from the scripts menu, and click the "use all above" button to autocheck the first four options. That should fix your issues with incorrect gamma on transparencies and bump and displacement.

Edit: I just realized there's no readme with the download. You place the SceneFixer.py file in your main Poser runtime in Program Files. In runtime>python>poserscripts>scriptsmenu

Edit2: I recommend reading the forum posts to get an idea of how it works and what you can do with it. :)

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PoserPro 2014, PS CS5.5 Ext, Nikon D300. Win 8, i7-4770 @ 3.4 GHz, AMD Radeon 8570, 12 GB RAM.