Pencil

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This article is about the handwriting tool. For other uses, see Pencil (disambiguation).

Image:Mergefrom.gif It has been suggested that pencil lead be merged into this article or section. ([[{{{2|: talk:Pencil}}}|Discuss]])

Image:Selection of colored pencils.jpg

A pencil is a handheld instrument containing an interior strip of solid material that produces marks used to write and draw, usually on paper. The marking material is most commonly graphite, typically contained inside a wooden sheath. However, other marking materials are used, such as charcoal or cosmetics (as in an eyebrow pencil). Coloured pencils employ pigments, including those used in oil and watercolor paints. Pencils may also have an eraser or "rubber" attached to one end, typically by means of a metal ferrule. Unlike pencils, pens use a liquid marking material, ink.

1 Manufacture
2 Color of pencils
3 Shape of pencils
4 Pencils in space
5 Miscellaneous
6 See also
7 References
8 External links

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Manufacture

Image:Artwork 2b to 6b.jpg

Today, pencils are made industrially by mixing finely ground graphite and clay powders, adding water, forming long spaghetti-like strings, and firing them in a kiln. The resulting strings are dipped in oil or molten wax which seeps into the tiny holes of the material, resulting in smoother writing. A juniper or incense-cedar plank with several long parallel grooves is cut to make something called a slat, and the graphite/clay strings are inserted into the grooves. Another grooved plank is glued on top, and the whole thing is then cut into individual pencils, which are then varnished or painted.

Many pencils, particularly those used by artists, are labelled on the European system using a scale from "H" (for hardness) to "B" (for blackness), as well as "F" (for fine point). The standard writing pencil is "HB". However, artist's pencils can vary widely in order to provide a range of marks for different visual effects on the page. A set of art pencils ranging from a very hard, light-marking pencil to a very soft, black-marking pencil usually ranges from hardest to softest as follows:

Hardest

→

Medium

→

Softest

The American system, using numbers only, developed simultaneously with the following approximate equivalents to the European system.

Tone	U.S.		Europe
	#1	=	B
	#2	=	HB
	#2 ½ *	=	F
	#3	=	H
	#4	=	2H

* Also seen as 2 4/8, 2.5, 2 5/10, due to patent issues

Even though the natural deposits of pure graphite are tapped out, it is still possible to write the way Englishmen did centuries ago, without clay or wax additives leaving oily stains on paper. Chemical supply companies commonly sell 99.995% pure graphite rods in 3 mm and 6 mm diameters. The largest commonly available mechanical pencils ("lead holders") take 2 mm leads.

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Color of pencils

Pencils in the United States and Canada tend to be painted yellow on the outside. According to Henry Petroski, this tradition now extends to a majority of pencils worldwide, and began in 1890 when the L. & C. Hardtmuth Company of Austria-Hungary introduced their Koh-I-Noor brand, named after the famous diamond. It was intended to be the world's best and most expensive pencil, and at a time when most pencils were either painted in dark colors or not at all, the Koh-I-Noor was yellow. As well as simply being distinctive, the color may have been inspired by the Austro-Hungarian flag; it was also suggestive of the Orient, at a time when the best-quality graphite came from Siberia. Other companies then copied the yellow color so that their pencils would be associated with this high-quality brand, and chose brand names with explicit Oriental references, such as Mikado and Mongol.

Not all countries however use yellow pencils; German pencils, for example, are often green, based on the trademark colors of Faber-Castell, a major German stationery company.

common pencil colors
United States	Image:YellowPencil.jpg
Canada	Image:YellowPencil.jpg
Germany	Image:GreenPencil.jpg
India	Image:RedBlackPencil.jpg
Switzerland	Image:RedPencil.jpg
United Kingdom	Image:YellowBlackPencil.jpg

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Shape of pencils

Most pencils today are hexagonal in cross-section. This shape is comfortable to hold and will cause the pencil to a stop if rolling on a desk. Carpenter's pencils have a flattened shape, and allow for a more precise positioning of the line drawn.

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Pencils in space

An urban legend in circulation since the 1970s (and told on a 2002 episode of The West Wing) tells of NASA spending large sums of money, typically in the millions of dollars, to develop an instrument that would write in space (a space pen). This task is not as simple as it seems, as standard ballpoint and fountain pens require gravity in order to function. The typical punch line is that either someone sends NASA a pencil, or that the Soviets used pencils.

While humorous, the story is not true (See Snopes for details). Writing with a pencil produces graphite dust, which when weightless, would float about the cabin. From there, it could become a health risk by being inhaled by the astronauts, clog filters in the ventilation system, or even cause short-circuits by getting into switches and other electrical equipment.

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Miscellaneous

The pencil is a common cause of minor puncture injuries in young children. The tip of the lead may leave a grey mark inside the skin for years. This led to the old wives' tale that the lead bits could be passed through the blood vessels into the brain, causing mental retardation in those with such a wound. Of course, pencil lead is graphite (carbon), and not the element lead, so it is not poisonous.

On March 30, 1858, Hymen Lipman of Philadelphia, Pennsylvania, USA, received the first patent for attaching an eraser to the end of a pencil. It was later invalidated because it was determined to be simply a composite of two devices rather than an entirely new product.

There is also a new mechanical pencil, which uses mechanical methods to push lead through a hole at the end. The erasers are also enabled to come off so the user can insert new lead. Lead types are based on thickness. Known types are .2, .5, .7, 1.0, and 1.5.

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References

Petroski, Henry (1990). The Pencil: A History of Design and Circumstance. New York: Alfred A. Knopf. ISBN 0394574222; ISBN 0679734155.
Petroski, Henry. H. D. Thoreau, Engineer. American Heritage of Invention and Technology, Vol. 5, No. 2, pp. 8-16.

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