Eraser

An eraser (also known as a rubber in some Commonwealth countries, including South Africa[1][2][3] from which the material first used got its name) is an article of stationery that is used for removing marks from paper or skin (e.g. parchment or vellum).

Bits of rough stone such as sandstone or pumice were used to remove small errors from parchment or papyrus documents written in ink.

"[4] In 1770 English engineer Edward Nairne is reported to have developed the first widely marketed rubber eraser, for an inventions competition.

The invention was described by Joseph Priestley on April 15, 1770, in a footnote: "I have seen a substance excellently adapted to the purpose of wiping from paper the mark of black-lead-pencil.

On March 30, 1858, Hymen Lipman of Philadelphia, United States, received the first patent for attaching an eraser to the end of a pencil.

Originally made from natural rubber, but now usually from cheaper SBR, this type contains mineral fillers and an abrasive such as pumice with a plasticizer such as vegetable oil.

Engineers favor this type of eraser for work on technical drawings due to their gentleness on paper with less smearing to surrounding areas.

More recently, very low-cost erasers are manufactured from highly plasticized vinyl compounds and made in decorative shapes.

Kneaded erasers (called putty rubbers outside the United States) have a plastic consistency and are common to most artists' standard toolkit.

Commonly sold in retail outlets with school supplies and home improvement products, this soft, malleable putty appears in many colors and under numerous brand names.

Poster putty does not erase so much as lighten by directly pulling particles of graphite, charcoal or pastel from a drawing.

Repeatedly touching the putty to a drawing pulls ever more medium free, gradually lightening the work in a controlled fashion.

Poster putty can be shaped into fine points or knife edges, making it ideal for detailed or small areas of work.

Poster putty loses its efficacy with use, becoming less tacky as the material grows polluted with debris and oils from the user's skin.

Chalk writing leaves light-colored particles weakly adhering to a dark surface (e.g., white on black, or yellow on green); it can be rubbed off with a soft material, such as a rag.