what does the b in hb pencil stand for
Pencil Most manufacturers, and almost all in Europe, designate their pencils with the letters H (commonly interpreted as "hardness") to B (commonly "blackness"), as well as F (usually taken to mean "fineness", although F pencils are no more fine or more easily sharpened than any other grade. Also known as "firm" in Japan[68]). The standard writing pencil is graded HB.[69] This designation might have been first used in the early 20th century by Brookman, an English pencil maker. It used B for black and H for hard; a pencil's grade was described by a sequence or successive Hs or Bs such as BB and BBB for successively softer leads, and HH and HHH for successively harder ones.[70] The Koh-i-Noor Hardtmuth pencil manufacturers claim to have first used the HB designations, with H standing for Hardtmuth, B for the company's location of Budějovice, and F for Franz Hardtmuth, who was responsible for technological improvements in pencil manufacture.[71][72]