What is that roughly textured squeaky plastic called?

Question

I need to know the type of plastic that's roughly textured and when you scratch it it makes a squeaky sound. It's usually used for holograms and folders and things like that.

Answer 1

usually mylar

Answer 2

It sounds like you're referring to a LENTICULAR image. The rough texture is created by lenticules (ribs). Each lenticule works as a magnifying  glass displaying portions of a interlaced (interweaved) image under it. Lenticular images are often confused with holograms. A good description of a lenticular image can be found at:

http://www.extremevision.com/content/edu...