Paper is made from new fibres or recycled material. Wood pulp is obtained by cutting down trees and breaking down the wood. The bark and chippings are then removed and ground down or cooked with chemicals to extract the cellulose fibres. Softwood trees are traditionally used to create wood pulp as the fibres are longer, making stronger paper; some manufacturers plant new trees for each one they chop down.
The pulp is filtered, squeezed, bleached and pounded before other materials, such as chalk or chemicals, are added to change the opacity and absorbency of the paper – this is called sizing. The excess water and chemicals are drained out of the pulp by pushing it through sets of rollers, called ‘calenders’, before being shaken and blown to dry out the fibres. This process is repeated until the pulp is fully dried, and then it is pressed to create a smooth finish.