When the first digital cameras created BMP or so for output, sending it to a monitor (or TV or else) in a CM-less environment made it look ugly thanks to the monitors non-linearity. Correcting the image made the hardware compensation to be baked into the image, and it was time-consuming to do all those corrections. For video reproduction on TV, things were even worse as the player had to perform the corrections while streaming to the screen.

Therefore, JPG (and MPG) were introduced, having the sRGB / non-linearity correction embedded by the device creating the image or video. Now, images and video could be dumped right onto the screen while still looking good. This enabled cheap DVD-players for MPG playback, and prevented most photo-enhancing from baking hardware specifics into the image.

While Photoshop takes the embedded correction out of the JPG before displaying and manipulating it, Poser up till now did not, but PP2010 does via the GC-feature. From this point of view, and from the point that rendering does require linear input, it's not really a feature but a fix of the failure to handle the JPG format properly. But okay, it serves more purposes than this one only and one can argue that linear rendering is  the feature at hand, so no hard feelings.

So, while CM on your system or the use of Photoshop (or both) make the PP2010 GC-feature sort of redundant, saving any texture to JPG immediately brings its relevance back again. Hence, for JPG images in the diffuse/color channels, GC should be used at the usual gamma=2.2 setting. By the way, the same holds for PNG although more variations may occur. For other image formats, GC should be used for textures not made in Photoshop on machines without CM enabled (pre-Vista etc). In all other cases, and for the other channels, GC should be off (or; gamma =1).

- - - - - 

Usually I'm wrong. But to be effective and efficient, I don't need to be correct or accurate.

visit www.aRtBeeWeb.nl (works) or Missing Manuals (tutorials & reviews) - both need an update though