(edit - cross-post) Was called away from computer before I saved this, hence repeating some of what hborre said.

The default texture for V4 was designed to appear a reasonably good shade under the lighting you would normally use for a non-gamma corrected image.

You change two things when you switch on scene gamma correction in Poser Pro, and both of these things will make this texture look wrong in a gamma-corrected image.

1. Your incoming texture maps are anti-gamma corrected before being used in the render. This is because most textures have gamma correction built into them, and this needs to be cancelled out before rendering. If you know for certain that a texture map you are using does not have any gamma correction in it, then you can turn it off in the Material Room by setting the GC value to 1.0.

2. You increase the overall brightness of your image. With GC on, you don't need anywhere near the light intensity that you would use without it.

However, the too-deep fall-off of the shadows in your non-GC render are typical, and are totally unrealistic.

"If I were a shadow, I know I wouldn't like to be half of what I should be."
Mr Otsuka, the old black tomcat in Kafka on the Shore (Haruki Murakami)