Tin foil is very thin silvery white, shiny sheet metal, in fact, tin foil is an aluminium foil.
But colloquially known as tin foil in Hong Kong and many other countries. In fact, today it is not derived form tin and does not contain tin at all, the name is derived from a foil made from tin back maybe 50+ years ago and the name has carried on even though the product [tinfoil] has been long discontinued.
In the processing of tin foil [now aluminium foil] the standard thickness should be 0.2mm or less per sheet. It is mainly used to make a number of easy to clean containers in the food and catering industry. Thousands of tons of aluminium foil around the world are used as a protective and packaging container for food, cosmetics and chemicals.
Most aluminium foil products have a shiny side, the other side matt. However, contrary to public opinion there is no advantage to be gained in heat transfer or safety from wrapping food in one side or the other. It is simply an old wives tale, a fallacy.
Because the term Tinfoil is so entrenched in many peoples mind, it often raises the question of health and safety in food preparation and containers designed for food. It is important to understand that tinfoil is no longer produced, so the risks that were associated with that product simply no longer exist. Howe ever it should also be noted that despite the claims that the high meting point of aluminium makes it safer for branching, frying and boiling, aluminium can, and does, under certain conditions leach out of cooking containers and can be taken into the human bio system, Although aluminium as such is toxic to humans, small amounts are usually not fatal, however it can build up inside the body. One dangerous side effect is created as aluminium is a counter agent to calcium which can impact on bone development, especially serious in children and woman.
It is wise not to use strong acidic spices or flavouring in the presence of aluminium and to check cooking pots etc carefully, especially, as they age, for signs of discolour or pitting. In such cases, it is wiser to discard the pot and invest in a Teflon coated product.