|
Manufacturers distinguish their pencils by grading them, but there is no common standard.<ref>{{cite web |url=https://pencils.com/hb-graphite-grading-scale |title=Graphite Grading Scales Explained |access-date=2017-02-05 |url-status=live |archive-url=https://web.archive.org/web/20170206105031/https://pencils.com/hb-graphite-grading-scale/ |archive-date=6 February 2017 |date=2014-11-08 }}</ref> Two pencils of the same grade but different manufacturers will not necessarily make a mark of identical tone nor have the same hardness.{{efn|Pencil grades vary "depending upon the manufacturer, when the pencils are made, and the source of graphite and clay. One analyst found that graphitic carbon content, for example, to vary from about 30 to about 65 in a variety of different pencils bearing the same designation." [[#Petroski 1990|Petroski 1990]], p. 229}}
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 knownreferred as "firm" inby Japanmany manufacturers<ref>[http://www.mpuni.co.jp/museum/qa/mistery05.html えんぴつのナゾを解く] {{webarchive|url=https://web.archive.org/web/20151003141714/http://www.mpuni.co.jp/museum/qa/mistery05.html |date=3 October 2015 }}. [[Mitsubishi Pencil Company]] {{inlang|ja}}.</ref><ref>{{cite web|url=https://www.koh-i-noor.cz/en/history|title=KOH-I-NOOR HARDTMUTH HISTORY.|publisher=Koh-I-Noor Hardtmuth|access-date=5 July 2024}}</ref><ref>{{cite web|url=https://www.faber-castell.com/-/media/Faber-Castell-new/PDF/en/Castell-9000-en.ashx|title=Castell 9000 brochure|publisher=Faber-Castell|access-date=5 July 2024}}</ref>). The standard writing pencil is graded ''HB''.<ref>[https://pencils.com/hb-graphite-grading-scale/ "Graphite Grading Scales Explained"] {{webarchive|url=https://web.archive.org/web/20170206105031/https://pencils.com/hb-graphite-grading-scale/ |date=6 February 2017 }}. Pencils.com.</ref>{{efn|This is not related to the [[Brinell scale]] hardness unit HB.}} This designation, in the form "H. B.", was in use at least as early as 1814.<ref>{{cite book |title=Memoirs, Including Original Journals, Letters, Papers, and Antiquarian Tracts, of the Late Charles Alfred Stothard, F.S.A. |first=Charles |last=Stothard |publisher=Longman |year=1823 |format=letter dated 1814 |url=https://books.google.com/books?id=aw1fAAAAcAAJ&dq=%22marked+H.+B.%22&pg=PA154}}</ref> Softer or harder pencil grades were described by a sequence or successive Bs or Hs such as ''BB'' and ''BBB'' for successively softer leads, and ''HH'' and ''HHH'' for successively harder ones.<ref>[[#Petroski 1990|Petroski 1990]], p. 157</ref> 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 [[České Budějovice|Budějovice]], and ''F'' for Franz Hardtmuth, who was responsible for technological improvements in pencil manufacture.<ref>{{cite web | url=http://www.koh-i-noor.cz/en/interesting-information-about-the-company | title=Interesting information about the company | publisher=Koh-I-Noor Hardtmuth | access-date=12 October 2016 | url-status=live | archive-url=https://web.archive.org/web/20161013001501/http://www.koh-i-noor.cz/en/interesting-information-about-the-company | archive-date=13 October 2016 | df=dmy-all }}</ref><ref name="The New Yorker April 28, 2016">{{cite magazine |last=Norris |first=Mary |author-link=Mary Norris (copy editor) |url=https://thescene.com/watch/thenewyorker/comma-queen-on-impact |format=Video |title=Comma Queen: On "Impact" |magazine=The New Yorker |publisher=Condé Nast |date=28 April 2016 |page=2:35 |access-date=14 May 2016 |url-status=live |archive-url=https://web.archive.org/web/20160605053709/https://thescene.com/watch/thenewyorker/comma-queen-on-impact |archive-date=5 June 2016 }}</ref>
As of 2021, a set of pencils ranging from a very soft, black-marking pencil to a very hard, light-marking pencil usually ranges from softest to hardest as follows:
|
