Starting in the 1970s, people began experimenting with metal for folding. Two main kinds of metallic papers are tissue foil and foil backed paper. Foil backed paper is one layer of foil attached to a layer of paper. The foil makes shaping and folding models with many layers easier. However, the shiny metal often distracts from the model and looks unnatural. Also, even the slightest dents show up on your creation.

Tissue Foil has foil on the inside surrounded by tissue paper. The "sandwhich" has more foil then the above and can be easily shaped.

Robert Lang's info about metallic papers