Is there a difference? Yes. Is it enough difference to bother with? In this lighting, probably not. I suspect there would be a noticeable difference with a strong rimlight and/or little lighting from front, but Poser is munching on another render right now, so I can't check. I might try it in a bit when that finishes. I took the ambient spot image, layered it over the SSS spot image, set the layer style to "difference" to show where the pixels are different, and then a rather severe level adjustment layer over that. (It's multiplying the color difference by a factor of 16, to tell you how severe.) You can see there is a (technically) difference in shading between the two. However, without the level adjustment, this image might as well be all black. It's not significantly percievable. If there was a render time difference, I'd suggest just using an ambient in this lighting situation. I don't know if there is a time difference. Is there, like, a python script or something that can time a render? I'd like to give it a go. ^_~ BTW, I'm not trying to be argumentative. It's just my engineering nature. In God we trust; all others bring data. ^_~