50 CFR 91.15 - Suitability of entry for engraving.
All entries should be drawn with fullest attention to clarity of detail and the relationship of tonal values. These prerequisites are important to interpret pictorial elements to hand engraving for printing, as they determine the engraved line techniques and direction. The engraver relies on the accuracy of the artist's work for successful interpretation. The engraver is primarily responsible for line interpretation and discipline, creating the miniature image of bird(s) appearing on the stamp.