Where does this come from, and can I check it?

Pencil letters H and B measure graphite hardness and blackness intensity. The figure is taken from Encyclopaedia Britannica, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.

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Yes. It sits on the Everyday Life shelf, one of 1,090 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.

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HB on standard pencils indicates a balanced medium lead hardness

Pencil letters H and B measure graphite hardness and blackness intensity

Pencil grading scales use H for hardness and B for blackness, with HB representing the central balanced grade. The graphite core contains a baked mixture of graphite powder and clay binder. Higher H numbers indicate more clay and lighter lines, while higher B numbers contain more graphite for darker marks.

Where this comes from

Encyclopaedia Britannica

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Tags: pencils, stationery, writing

HB on standard pencils indicates a balanced medium lead hardness: the short answers

Where does this come from, and can I check it?: Pencil letters H and B measure graphite hardness and blackness intensity. The figure is taken from Encyclopaedia Britannica, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
Is this really a everyday life fact?: Yes. It sits on the Everyday Life shelf, one of 1,090 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.
What else can I read about it?: The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.