Why is aluminum foil shiny on one side but dull on the other?
It has to do completely with the manufacturing process and that's it During the final rolling two sheets are together at the same time through the rollersThe inside faces stay dull while the outside faces become shiny due to the rollers Some people say the shiny side reflects heat better and the dull side absorbs it betterThough in theory this is true, it has little effect.
