A fundamental requirement for the recycling of printed matter is the removal of the ink and other substances with which it has been printed and treated.
Removing ink from the printed matter is necessary to create a clean raw material, something suitable for turning into new paper products. The cleanliness of the raw material determines its suitability for subsequent re-use, ranging from graphic papers to paperboard to tissue. For decades offset, gravure and dry toner-based digital prints have been processed into pulp for new papers of all types without much difficulty. However, the explosion in new imaging technologies and colourants is causing considerable worries for the established pulp production models and consequently for recycling.
The processing of recycling paper into new paper products depends on the composition of the raw material, deinking chemistries and the pH of the processing solution, including any bleaching and washing requirements. Many pulp production and recycled paper manufacturing models quite reasonably assume that the raw material will be a mix of newsprint, gravure, offset and dry toner prints.