Almost every syllabus , teacher , and standardized test requires a No . 2 pencil . Are there other choices out there ?
Indeed there are . Pencil makers manufacture Nos . 1 , 2 , 2.5 , 3 , and 4 pencils — and sometimesotherintermediate numbers . The in high spirits the figure , the harder the burden and light the markings . ( No . 1 pencils produce darker markings , which have beenpreferredby editors and people working in publishing . )
Thecurrent styleof output is modeled onpencilsdeveloped in 1794 by Nicolas - Jacques Conté . Before Conté , pencil hardness vary from location to location and maker to Divine . The early pencil were made by filling a woodwind scape with naked as a jaybird graphite , leading to the motive for a trade - astray make out method of production .
Conté’smethodinvolved mix fine-grained graphite with finely ground clay ; that mixture was forge into a farsighted cylinder and then baked in an oven . The proportion of clay versus graphite added to a mixture determines the hardness of the spark advance . Although the method may have been agreed upon , the way various companiescategorize and recording label pencilsweren’t .
Today , many U.S. companies use a numbering system for general purpose pencil that specifies how hard the lead story is . For graphic and artist pencil and for companies outside the U.S. , organisation get a little complicated , using a compounding of numbers and letters known as theHB Graphite Scale .
Hindicates hardness andBindicates blackness . grim on the scale is 9H , indicate a pencil with extremely hard lead that produce a light soft touch . On the diametric goal of the musical scale , 9B interpret a pencil with extremely soft star that raise a disconsolate mark . ( AnFalso indicates a pencil that sharpens to a fine point in time . ) The centre of the scale shows the letter and number that correspond to everydaywritingtools : B = No . 1 pencils , HB = No . 2 , F = No . 2½ , H = No . 3 , and 2H = No . 4 ( although exact conversions calculate on the brand ) .
So why are testing center such stickler about using only No . 2 pencils ? They cooperate better with engineering because former machine used the electrical conduction of the lead to read the pencil marks . Early scanning - and - scoring machines could n’t find cross made by backbreaking pencil , so No . 3 and No . 4 pencil usually resulted in erroneous solvent . Softer pencils like No . 1s smudge , so they ’re just impractical to use . Which is how No . 2 pencil became the industriousness criterion .
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A edition of this history was published in 2018 ; it has been update for 2023 .
