One method for the assessment of the recyclability of graphic paper products is the deinkability test (removability of printing inks) according INGEDE method 11 on a laboratory scale.

The printed paper products are desintegrated under alkaline conditions and the pulp produced is then treated to a single-loop flotation deinking process. The main steps of the deinking process are the detachment of the printing inks from the fibres, the fragmentation of the printing inks into separable sizes and their removal via the pulp sludge.

The test is evaluated on laboratory sheets of the pulp before and after the deinking step. For the evaluation, various optical quality parameters are determined according to INGEDE method 2, for example:

• reflectance factors,
• light absorption and scattering co-efficients,
• ERIC,
• colour values and
• dirt specks.

The deinkability rating is based on the INGEDE-2 parameters and an assessment according the Deinking Scorecard of the European Paper Recycling Council.