I took an image I made in pymol with an opaque background, then added either a black or white background in photoshop (see attached file), to demonstrate the problem I'm having. The depth cue fog in the black background image looks great (light in front, fades to dark), but the white background looks awful (darker in front, lighter backgound--looks oddly "backlit"). I think this might be an optical illusion caused by the white fog tint. I would like to try darkening the fog tint to see if I can improve the white background image. Is there a way to do this? If not, do you have any suggestions to deal with this problem?