I think I was using BB's EnvSphere w/ a blue sky/forest map I had downloaded from one of the links on his site. I also use Gamma Correction and IDL (setting the gamma in/out on the envsphere to 1/1 per his notes).

Not sure how much of a difference it makes, but my Texture Filtering on the color map is 'none' (I never leave it on the 'quality' default). I also uncheck that Reflection box on the Poser Surface node.

/edit

Here's the link to the Envsphere.

https://sites.google.com/site/bagginsbill/free-stuff/environment-sphere

And a link to one of the maps I use. I use render gamma for it when I load it into the envsphere.

https://www.flickr.com/photos/pedroscreamerovsky/6839820804

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