Quality A: Live knots up to 10 mm; some black pin knots up to 3 mm; even color.
Quality B: Live knots up to 35 mm; black knots and holes up to 10 mm; sapwood up to 5 mm; natural healthy variations in color and structure; repair of dead knots is allowed.
Quality D: Live knots, dark solid knots, and fallen knots without restriction; cracks up to 400 mm (that do not affect strength); slight discoloration (sleep); natural color variation; ingrown bark up to 150 mm; heartwood. Repair of defects: no repair with putty allowed; panels with open finger joints allowed.
Quality Design: Color with smooth transitions between sapwood and heartwood.