Why are pencils yellow, and what does No. 2 mean?

Pencils are yellow because of a luxury pencil launched in 1889, which other makers copied until yellow became the default. The number 2 is a hardness grade: a middle setting that writes dark enough to read and stays hard enough to hold a point. The color has nothing to do with the grade, and the exact reason for choosing yellow is less certain than popular accounts suggest. [1] [2]

According to the Paris World's Fair story, the Hardtmuth company of Bohemia introduced a premium pencil called Koh-I-Noor in 1889, named after the famous diamond and painted yellow. Before that, pencils were often painted to hide low-quality wood, and only the fanciest went unvarnished. The luxury pencil's marketing worked, and copycats began painting their own pencils yellow too. Henry Petroski's history of the pencil, as reported by one source, says that about a hundred years later roughly three in four pencils made were yellow. [3] [2] [1]

Today there is no standard yellow. Scott Johnson of Musgrave Pencil Company says each company has its own proprietary shade, and that color does not affect how a pencil performs. He also notes that a pencil works as a small billboard, and that yellow is eye-catching. [1]

The most common explanation is that the best graphite of the late 1800s came from China, where yellow was linked to royalty, so the color advertised both the graphite's source and its quality. Reader's Digest and the Musgrave president Scott Johnson present this account, with yellow standing for luxury, elegance and quality. [1] [4]

A different suggestion ties the color to the yellow of the Austro-Hungarian flag, and the GBH piece says the pencil was painted yellow perhaps to honor the empire's flag. One of the sources cautions that simplified origin stories should be treated carefully. The results do not settle the matter, though they agree that the 1889 Koh-I-Noor launched the trend. [3] [2] [5]

A pencil core is a mix of graphite and clay. More clay makes a harder core and a lighter line, while more graphite relative to clay gives a softer, darker one. American pencils use numbers, where higher means harder, and most makers elsewhere use letters, with H for hard and B for black. The Metropolitan Museum of Art describes the No. 2 as medium in tone and equivalent to HB. [6] [2] [1]

The equivalence is approximate. One source reports a pencil seller saying there is no industry standard for the darkness of the mark in any grade, so each manufacturer sets its own and one brand's No. 2 can differ from another's. Japanese buyers are said to prefer softer, darker leads than European ones. [2] [5]

The No. 2 is a compromise: dark enough to read, hard enough to resist smudging and keep a point. Standardized tests reinforced the habit, since the scanning machines needed marks they could read. Johnson says it was dark enough for the machines yet hard enough to erase cleanly. One report on SAT sheets says the consensus is that scanners read a No. 3 mark just as well, so the rule was looser than it sounds. A No. 2 can be any color, and the link to yellow is cultural rather than technical. [1] [2] [5]