I tried your suggestions, which worked quite well. Thank you. Both specularity and ambience need to be applied with caution, as too much really flashes out the image. But the middle example with white specularity and blue halo really adds lively color vs the original (on left). The jury is still out on ambience. Too much and the 3D form is washed out. Still, adding a little set at deep red puts interesting color into the shadows. The affect would likely be better if I went back and adjusted lighting everywhere else. I'll try this on future renders.