Pencil


A very simple pencil

A pencil is a handheld instrument used to write and draw, usually on paper. The writing is done with graphite (except for colored pencils), which is typically covered by a wooden sheath. Pencils may also have an eraser or "rubber" attached to one end: a difference with the pen is that erasing is easy.

Table of contents
1 History
2 Manufacture
3 Hardness Scales
4 Different forms of pencils and related tools
5 See also
6 External Links

History

The prototypical pencil may have been the ancient Roman stylus, which was a thin metal stick used for scratching on papyrus, often made of lead. The word pencil comes from the Latin word "penicillus" which means "little tail".

In 1564 on the side Seathwaite Fell near Borrowdale, Cumbria, England, an enormous deposit of graphite was discovered. The locals found that it was very useful for marking sheep. This particular deposit of graphite was extremely pure and solid and it could easily be sawn into sticks. This was and remains the only deposit of graphite ever found in this solid form. Chemistry was in its infancy and the substance was thought to be a form of lead. Consequently it was called plumbago (Latin for acts like lead). The black core of pencils is still called "lead", even though it does not contain the element lead.

The value of plumbago was soon realised to be enormous, mainly because it could be used to line the moulds for cannon balls, and the mines were taken over by the Crown and guarded. Graphite had to be smuggled out for use in pencils. Because the plumbago was soft, it required some form of case. Plumbago sticks were at first wrapped in string or in sheepskin for stability. The news of the usefulness of these early pencils spread far and wide, attracting the attentions of artists all over the known world. It was the Italians that first thought of wooden holders, at first by hollowing out a stick of cedar. Shortly thereafter, a superior technique was discovered: two wooden halfs were carved, a plumbago stick inserted, and the two halfs then glued together -- essentially the same method that is in use to this day.

Although deposits of graphite had been found in other parts of the world, they were not of the same purity and quality as the Borrowdale find, and had to be crushed to remove the impurities, leaving only graphite powder. England continued to enjoy a monopoly on the production of pencils until a method of reconstituting the graphite powder was found. The distinctively square English pencils continued to be made with sticks cut from natural graphite into the 1860s. Today, the town of Keswick, near the original findings of block graphite, has a pencil museum.

The first attempt to manufacture graphite sticks from powdered graphite was in Nuremberg, Germany in 1662. They used a mixture of graphite, sulphur and antimony. Though usable they were inferior to the English pencils.

English and German pencils were not available to the French during the Napoleonic wars. It took efforts of an officer in Napoleon’s army to change this. In 1795 Nicholas Jacques Conté discovered a method mixing powdered graphite with clay and forming the mixture into rods which were then fired in a kiln. By varying the ratio of graphite to clay, the hardness of the graphite rod could also be varied (the more clay, the harder the pencil, and the lighter the color of the mark). This method of manufacture remains the one in use today.

Manufacture

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 cedar plank with several long parallel grooves is cut, the graphite/clay strings inserted, another plank glued on top, and then cut into individual pencils. These are then varnished.

Hardness Scales

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 range from hardest to softest as follows:

9H 8H 7H 6H 5H 4H 3H 2H H F HB B 2B 3B 4B 5B 6B 7B 8B 9B 

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

#1  =  B
#2  = HB -- most common
#2˝ =  F -- also seen as 2-4/8, 2.5, 2 5/10 due to patent issues
#3  =  H
#4  = 2H

Different forms of pencils and related tools


Coloured & artists pencils

Aside from the above range from the lightest of grey to the darkest of blacks, coloured pencils (also called "pencil crayons") are also available. These are versatile, and can be used for tasks as varied as colouring in a child's colouring book or creating life-like renderings. They do not contain graphite, but rather a core consisting of pigment bound to gum and clay.

The core of pencils wears down as it is written with (it is literally left behind on the paper), and the wooden or plastic sheath must be sharpened away to reveal more of the core. This can be done with a pocket-knife or special "pencil sharpener." These can be as simple as a small blade encased in a square of metal, or as elaborate as electronic, pressure sensitive, "automatic sharpeners."

In the art world, the pencil has traditionally been seen as an instrument for impromptu sketching to remember a composition for later, or as a way to mark lightly and map out a drawing before commencing the "real" art (usually painting). However, it is safe to say that the pencil has come to be viewed as an art medium in its own right.

Hyman L. Lipman of Philadelphia patented a pencil with an attached eraser on March 30, 1858. The metal ring which is crimped to hold the eraser in place is known as a ferrule.

A "mechanical pencil" or "propelling pencil" is one in which the graphite core can be refilled over and over, by inserting it into the removable cap and clicking the mechanism to feed out the desired amount of graphite as it wears down. These were widely used in the Victorian era, when pencil casings were often made of precious metal, and intricately carved.

See also

External Links




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