Scratch and Dig
Although this standard is based on comparison to a certified optical comparator, the following general guideline is commonly accepted when referencing a scratch and dig specification: The first number represents the maximum allowable scratch width in microns (20/10 = no scratches greater than 20um wide allowed). The second number represents the maximum allowable dig in 10's of microns as measured LxW/2 (20/10 = no digs greater than 100um allowed).
A scratch and dig spec can be written and inspection standard developed around any known requirements. The sample specifications listed below are intended to provide a general guideline and encompass the most commonly used values.
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