(a) A potato is practically free from a named injury to the appearance if the injury is not readily apparent on casual examination and if damaged areas can be pared without appreciable waste in excess of that which occurs with perfect potatoes. Loss of the outer skin only is not an injury to appearance.
(b) The diameter of a potato is the greatest dimension at right angles to the longitudinal axis.
(c) A potato is free from serious damage if the appearance of the potato is not damaged from a named injury over more than 20 percent of the surface and if the damage can be removed by paring with waste of not more than 10 percent by weight in excess of that which occurs with perfect potatoes.