Thanks for getting back to me.

Yes, I found the control and have been experimenting with it all morning. I had abandoned IDL for low light renders because of the issues you describe, but now find, like you, my old friend is back regardless of what lighting effect I want.

And I hope you didn't think me mean for asking you to post the control location. It seems to me that in these threads all too often we assume that everyone knows what we know and feel it is a waste of time to fill in the details. There have been many times when I've asked questions here and gotten very accurate answers that made no sense at all to me. I was especially touched by an answer from Bagginsbill. He first gave me the advanced user answer. When I responded with "Huh?" he then gave me a very detailed, step by step solution to my issue that actually helped and solved my problem! We have so much expertise available in these threads... we just have to make sure that we communicate what we know in a way that is useful. Makes for a tough world, doesn't it?

Again, thanks so much for getting back to me and sharing this tidbit!