Eraser: Difference between revisions

Content deleted Content added

Inline

Revision as of 00:04, 4 January 2011

An eraser (US) or rubber (UK) is an article of stationery that is used for rubbing out pencil and also for pen mistakes. Erasers have a rubbery consistency and are often white or pink, although modern materials allow them to be made in any color. Many pencils are equipped with an eraser on one end. Typical erasers are made from synthetic rubber, but more expensive or specialized erasers can also contain vinyl, plastic, or gum-like materials. Other, cheaper erasers can be made out of synthetic soy-based gum.

History

Prior to the invention of the rubber eraser, tablets of wax were used to erase lead/charcoal marks from paper. Bits of rough stone such as sandstone or pumice were used by various cultures to remove small errors from parchment or papyrus documents written in ink. It has been claimed that crustless bread was, in the past, commonly used as an eraser; this is possible, but the bread would disintegrate, and would at that time most likely have been too costly to replace. In all likelihood this was probably more of a snide commentary on low quality bread, comparing it to a chunk of wax or sanding stone.

On April 15, 1770, Joseph Priestley described a vegetable gum which had the ability to rub out pencil marks: "I have seen a substance excellently adapted to the purpose of wiping from paper the mark of black lead pencil." He dubbed the substance "rubber".^[1]^[2]

In 1770, Edward Nairne, an English engineer, is credited with developing the first widely-marketed rubber eraser for an inventions competition. He reportedly sold natural rubber erasers for the high price of 3 shillings per half-inch cube. According to Nairne, he inadvertently picked up a piece of rubber instead of breadcrumbs, discovered rubber's erasing properties, and began selling rubber erasers. Incidentally, this was the first practical application of the substance in Europe, and rubbing out the pencil marks gave it its English name.

However, rubber in its raw form shared the same inconveniences as bread, since it was perishable and would go bad over time. In 1839, inventor Charles Goodyear discovered the process of vulcanization, a method that would cure rubber and make it a durable material. Rubber erasers became common with this advent of vulcanization.

On March 30, 1858, Hymen Lipman of Philadelphia, 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.^[3]

Types

Art gum erasers

Another eraser type that is popular with artists is the art gum eraser, made of soft, coarse rubber. It is especially suited to removing large areas, and it does not damage the paper. However, they are not very precise. Gum erasers tend to crumble as they are used, so this type leaves a lot of eraser residue. This "eraser dust" must then be brushed away with care, as the eraser particles can leave marks on the paper. Many artists use a broad brush to sweep away the loose eraser residue. Art gum erasers are commonly tan or brown.

Kneaded erasers

Kneader erasers are a type of eraser common to most artists' standard toolkit. This type has numerous uses. They can be pulled into a point for erasing small areas and tight detail erasing, molded into a textured surface and used like a reverse stamp to give texture, or used in a "blotting" manner to lighten lines or shading without completely erasing them. One weakness of this type is that they can gradually lose their efficacy and resilience as they become increasingly infused with particles they have picked up both from erasing and the environment around them. They are also not very effective at erasing large areas, as they tend to deform under vigorous erasing.

Electric erasers

File:Cheap electric eraser.jpg

A relatively cheap electric eraser with a small box of replacements

The electric eraser consists of a knob in a short, thin rod attached to a miniature motor. A button located on one side turns the motor on once pressed, and off when pressure is released from the button. As the knob of eraser turns at a relatively rapid speed, it achieves a smooth and complete area of erasure with a minimum of trauma to the paper. The main purpose this device is designed for is erasing pencil lines or shading completely and precisely in a short time, compared to using a kneaded eraser.

Soft vinyl erasers

Soft vinyl a plastic-like texture and erase more cleanly than standard pink erasers. They are somewhat softer and non-abrasive, making them less likely to damage canvas or paper. They are prone to cause smearing when erasing large areas or dark marks, so these erasers are more frequently used for erasing light marks and precision erasing. Engineers favor this type of eraser for work on technical drawings due to their gentleness on paper. Vinyl erasers are commonly white.

Ink erasers

A less common type of eraser is used to erase pen. Pulverized pumice is blended into this type of eraser to make it abrasive. However these erasers also remove some layers of the paper so the paper becomes extremely thin and can tear. This eraser is typically a half pen eraser and a half "art gum" eraser. It is used by those who like the look of a pen and the changability of a pencil.

Others

Another type of eraser is used specifically for marks on a chalkboard or whiteboard. Rather than being rubbery or gummy like pencil erasers, it is a hand-held wooden or plastic block with a dark felt pad on one side.

Erasers come in several shapes and sizes. In addition to those that come attached to pencils, they may also be rectangular blocks (block and wedge eraser), or conical caps that can slip onto the end of a pencil (cap eraser). A barrel or click eraser is a device shaped like a pencil, but instead of being filled with pencil lead, its barrel contains a retractable cylinder of eraser material (most commonly soft vinyl). Novelty erasers are made in a wide variety of shapes, colors, and designs to suit their themes (such as musical notes, animals, confectionery), and they are typically acquired more for their decorative nature than for any practical use, as the hard vinyl they are made from tends to smear heavy markings.

References

^ "Joseph Priestley (1733-1804)". Retrieved 2009-06-30.
^ See the footnote on page xv at the end of the preface to the following: Priestley, Joseph (1770). A Familiar Introduction to the Theory and Practice of Perspective. London: J. John and J. Payne.
^ Reckendorfer v. Faber 92 U.S. 347 (1875)

Bibliography

Petroski, Henry (1989). The Pencil: A History of Design and Circumstance..

External links

Eraser: How Products are Made, Volume 5 (1997) by Rose Secrest
Pearlstein, E. J. (1982). "Effects of Eraser Treatment on Paper". Journal of the American Institute for Conservation. 22 (1): 1–2. doi:10.2307/3179714. JSTOR 3179714. {{cite journal}}: More than one of |number= and |issue= specified (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)
Goodyear Rubber History
All about erasers: history, classification, photo, collection
Internet-forum about erasers

[1] "Joseph Priestley (1733-1804)". Retrieved 2009-06-30.

[2] See the footnote on page xv at the end of the preface to the following: Priestley, Joseph (1770). A Familiar Introduction to the Theory and Practice of Perspective. London: J. John and J. Payne.

[3] Reckendorfer v. Faber 92 U.S. 347 (1875)

[1]

[2]

[3]

@@ Line 21: / Line 21: @@
 ===Art gum erasers===
 [[Image:Kneaded eraser.jpg|right|thumb|Two kneaded erasers. A new eraser is on the left, and an older eraser on the right. The older eraser is darker due to the graphite and charcoal dust that has become incorporated into the eraser.]]
-Another eraser type that is popular with artists is the ''art gum'' eraser, made of soft, coarse rubber. It is especially suited to removing large areas, it and does not damage the paper. However, they are not very precise. Gum erasers tend to crumble as they are used, so this type leaves a lot of eraser residue. This "eraser dust" must then be brushed away with care, as the eraser particles can leave marks on the paper. Many artists use a broad brush to sweep away the loose eraser residue. Art gum erasers are commonly tan or brown.
+Another eraser type that is popular with artists is the ''art gum'' eraser, made of soft, coarse rubber. It is especially suited to removing large areas, and it does not damage the paper. However, they are not very precise. Gum erasers tend to crumble as they are used, so this type leaves a lot of eraser residue. This "eraser dust" must then be brushed away with care, as the eraser particles can leave marks on the paper. Many artists use a broad brush to sweep away the loose eraser residue. Art gum erasers are commonly tan or brown.
 ===Kneaded erasers===