Paper is made from wood fibre originally from sawmills, recycled cloth, vegetable matter, and recycled newspaper. Different types of cellulose fibres from different types of wood are used in the production of paper in many cases.
While a lot of people go out of their way to make sure that they use recycled paper and this is certainly a good thing, it should be noted that many of the materials that are used to make paper in the first place are recycled. The paper that is made entirely from pure wood pulp is called virgin paper, and it is rarer than a lot of people think. A lot of paper is made from discarded paper material or recycled boards.
Paper weight is measured in grams – the grammage is a measure of the thickness of the paper. For instance, paper that might have a weight at the 140lb index level will have a grammage of 255 gsm. Paper that has a higher index level can actually be thinner in some cases than paper that has a lower index level. A higher grammage level is going to mean that the paper type in question is going to be heavier and thicker.