The viewing cabinet shall be situated in a darkened room. Place the tested specimen and a piece of the original sample, with or without pretreatment ,centrally on the lectern in the viewing cabinet, with the length direction vertical. If necessary use a piece of self-adhesive PVC tape to ensure correct placement. Mount the tested specimen on the left and the original sample on the right. In order to prevent glare from the light source view each specimen from just outside the viewing cabinet, directly in front of the specimen. Due to the subjective nature of the assessment, it is recommended that more than one observer assess the specimens. Grade each specimen in accordance with the grading scheme given in Table1. If the grading appears between two grades, report the“half”grading as,for example,3-4. The test result for each individual observer is the average off our specimen grades. The test result for the laboratory sample is the average of the observer grades. Phot...