I think the only allowed in stuff like photoshop or Corel photopaint should be greyscale maps for the terrain editor and texture maps for objects created in Bryce. If you truly want those effects in post work you can acheive them by creating them in Bryce. I haven't tried this but I suppose a depth of field effect could be acheived by using a transparent material with some fine noise mapped onto a sphere placing the object in focus and cammera within the sphere or at least somthing similar, IOW creating filters using objects. This was how my "sunflare test" was acheived if you do a search for it.