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To determine the adhesion property of the formulation, the wear assay can also be completed with a Scotch tape, in which the tape is placed on top of the sample and removed at a 90° angle. A similar visual assessment is made to analyze the quality of the sample. These visual inspections are then translated to a ranked scale. Figure 1.6 (right) shows what is considered to be a good and a bad sample after the test is completed. The long-wear lipstick formula would ideally have a higher adhesion to the substrate rather than to the tape, preventing any formulation from being removed.

Figure 1.6 Wear assay results indicating satisfactory (left) and unsatisfactory (right) resistance to oil and formulation adhesion (tape test).