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Pencil Hardness/Softness Ratings - The Pencil Pages
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日期:2024-10-09
An Article on the grading of pencils, ie. hardness designations. ... or Grading Pencils by Doug Martin November 3, 1997 Early pencils were made using cut pieces of raw graphite dug from the earth. The hardness or softness of these pencils was dependent on...看更多