Letter (paper size) "official" "Government Letter" size, , was used in government, while paper was standard in most other offices. In the U.S., paper density is usually measured in "pounds per ream" (of 500 sheets). Typical Letter paper has a basis weight of paper of – the weight of 500 sheets (a ream) of paper at and at 50% humidity. One ream of 20-pound Letter-sized paper weighs , and a single Letter-sized sheet of 20-pound paper weighs , which is equivalent to 75.19 g/m. Some metric information is typically included on American ream packaging. For example, 20-pound paper is also labeled as 75
Parchment paper Parchment paper Parchment paper and bakery release paper are cellulose-based papers that are used in baking as a disposable non-stick surface. Both are also called bakery paper or baking paper. They should not be confused with waxed paper, also known as wax paper or rarely as butter paper. Modern parchment paper is made by running sheets of paper pulp through a bath of sulfuric acid (a method similar to how tracing paper is made) or sometimes zinc chloride. This process partially dissolves or gelatinizes the paper. This treatment forms a sulfurized cross-linked material with high density, stability, and heat resistance,