I just ran into a vexing problem I've encountered before. It was before I knew about Adobe forums, and I never did get to the bottom of it.
I took a photo and extracted some people out of the background to place on the cover of a book--did this work in Photoshop. The background is now transparent as glass. But when I place it on the cover, create a pdf, and print the cover, the rectangular background shows up a shade lighter than the color the image is sitting on. I did not convert to Postscript before going to pdf--I've heard that Postscript and transparencies don't get along. So I know that's not the problem. Any other ideas?
It worked! Thank you, Bob!