Something that never crossed my mind. I was about to hang a shelf in my daughters room so I got out the stud finder and started looking. Thought the battery was dead as I received no signal across the whole wall. Changed it out and still no luck. I then realized that the wall, with an aluminum leaf finish, might be the problem. So I tried the stud finder on a painted wall and it worked fine. I am not really sure exactly how the stud finder works, but it makes sense that the metal leaf could cause interference. I will remember this for that job that might require things being hung back up when doing a metal leaf wall!