To produce paper, manufacturers have to convert wood (in the form of wood chips or sawmill residue) into paper pulp using a chemical or a mechanical pulping process.

Mechanical pulp is formed with the retention of lignin through the action of mechanical forces on wood. As the process yield is around 90-98%, the paper pulp industry generally needs to use bleaching agents (alkaline hydrogen peroxide or sodium dithionite) to prevent pale-yellow coloring of the pulp.