Sink mark visibility can be very subjective, and is often dependant on many factors such as lighting, surface texture and less tangible factors such as experience / expectation of the observer. Past research suggests that on textured surfaces sink mark depths of 0.040mm are generally not visible to the trained eye while sink marks deeper than 0.075 mm are evident even to the untrained eye. On high gloss surfaces sink marks less than 0.015 mm can be quite visible depending on light conditions.

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