Since the character sample book 2 is printed by the oily ink and by the dots, the density of the Indian ink in the portion copying on the character sample book 2 is visible thin and the density of the Indian ink in a portion projecting therefrom is visible dark and therefore, the workmanship thereof can be evaluated and a learning effect improves. 文字手本2は油性インクで、かつ網点で印刷されているので、文字手本2上に倣っている部分は墨の濃さは薄く、はみ出た部分の墨の濃さは濃く見えるため、その出来映えを評価でき、学習効果が向上する。 - 特許庁