2.2. Observation of Appearance
In accordance with the European pharmacy standards, we assessed the color and appearance of the force-degradation and normal samples. An inspection station was set up with a light box and a non-glare (matte finish) and white background equipped with a light source (fluorescent, cool light) capable of producing a light intensity of ≥ 150 footcandles. A photometer with a quantum photo meter or extech light meter and reference color solution (Cat. No. 1002670001 [Ph. Eur.] Merck, Rahway, NJ, USA) was used to measure the light intensity accurately.