![]() The truth of which has been lost over time but I kind of like the idea that Franz invented the pencil lead scale and named it after himself and where he worked. However German pencil manufacturers claim that it is a system that they used which predates Franz Hardtmuth with H representing Hardness and B represents blackness. Czechoslovakian pencil manufacturer Koh I Noor claims that the pencil lead hardness scale was invented in 1802 by Franz Hardtmuth with H representing the family name, F represents his first name, and B after a town called Budějovice where they made the pencils. There is some dispute as to who was the first to categorize pencils in this way. The graphite scale (lead hardness scale) is a visual means of categorizing the resultant marks from pencils with cores that have different ratios of graphite to clay. As the ratio of the graphite to clay is increased the core of the pencil writes increasingly dark marks but also becomes softer. Pencils with a high ratio of clay to graphite have a stronger lead core and produce light marks when writing on paper. How light or dark the pencil will write and how strong the lead core is depending on the ratio of the graphite to clay. The core of a wooden pencil or its “lead” is made up of a combination of graphite, clay, and other binders. ![]() Although it is still commonly referred to as pencil lead. Check out our post What is Pencil Lead Made Out of? for more information. Most people may know that pencil lead is not actually made from lead but from graphite which is a form of carbon. Drawing Realistic Textures in Pencil by J.D Hillary General Pencils Kimberly Graphite Pencil #525-9XXB
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