Quote - Here's a strange thing. Cath was talking about IBL Contrast and we have to guess at what it really does.

The previous render was with IBL Contrast = 1.

I lowered the contrast to .75 and strangely the contrast increased - not at all what is expected.

Setting it to 0 causes a very slow black render.

I don't have Poser 7, so excuse my ignorance if this isn't the case, but this looks to me like intensity color clamping.  HDR images, of course, have high contrast changes from pixel to pixel. One pixel may have an intensity value of 10, for instance, and the pixel right beside it may have a value of 10,000.  This kind of shift in dynamic range can be hard to control, so most apps that make use of HDRI offer some kind of clamping options.  Perhaps Contrast is the equivalent function in Poser?  Higher values mean more intensity clamping (of contrasting colors), while lower values mean less.  That would produce results similar to what you are seeing there.   Of course, this would also mean that a value of 0.0 could only be useful when secondary rays from true GI are employed.

If Cath tone-mapped her HDR images in some other application, then she wouldn't need this feature per-se, because her maps would already be clamped, and using any value other than 0.0 on her maps might give undesireable results.

Again, I'm just making a guess here based on some highend features I've worked with in other apps, so this may be TOTALLy incorrect for Poser, and I apologize if it leads to a dead end, or if it's already been explored before, and ruled out.  I didn't read this whole thread.

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Tools :  3dsmax 2015, Daz Studio 4.6, PoserPro 2012, Blender v2.74

System: Pentium QuadCore i7, under Win 8, GeForce GTX 780 / 2GB GPU.