Not the reflective kind. That is the extent of my densitometer knowledge. I was going to ask the same question.
Sorry I neglected to answer your offer. Sorry about that. I just might take you up on it when things quiet down here. In one month I will be able to breate again. The masters will be complete the teaching semester will be in full swing, and my son will have gotten over the seperation anxiety of me going back to work.
By the way how does one take a picture of a step wedge? Something I have always wondered.