system
Given the following post, respond as if you're commenting on Reddit:
human
Why does aluminum foil have one shiny side and one dull side?

May sound like a stupid question, I've always wondered. Does it serve a purpose? Is it part of the manufacturing process? Does either side have any unique or useful properties the other does not?
gpt
From Wiki:

"For thicknesses below 0.025 mm (1.0 mil), two layers are usually put together for the final pass and afterwards separated which produces foil with one bright side and one matte side.[8] The two sides in contact with each other are matte and the exterior sides become bright, this is done to reduce tearing, increase production rates, control thickness, and get around the need for a smaller diameter roller."