Carbon copy
A carbon copy is a method of document copying where the original document is placed over a sheet of carbon paper and a blank sheet, then pressure is applied on the original document, so the document is printed on the blank sheet with carbon.
When copies of business letters were so produced, it was customary to use the acronym "CC" or "cc" before a colon and below the writer's signature to inform the principal recipient that carbon copies had been made and distributed to the parties listed after the colon. With the advent of word processors and e-mail, "cc" is used as a merely formal indication of the distribution of letters to secondary recipients.
Process
A sheet of carbon paper is placed between two or more sheets of paper. Later, pressure is applied to the top sheet with a writing implement such as a pen, pencil, typewriter or impact printer. This causes pigment from the carbon paper to reproduce the similar mark on the copy sheet. More than one copy can be made by stacking several sheets with carbon paper between each pair. Four or five copies is a practical limit. The top sheet is the original and each of the additional sheets is called a carbon copy.History
was invented by Pellegrino Turri in 1801, but it did not become widely used for copying until typewriters became common. Carbon copies were in wide use between the 1870s and 1980s, largely for administrative tasks.Use
The use of carbon copies declined with the advent of photocopying and electronic document creation and distribution. Carbon copies are still sometimes used in special applications: for example, in manual receipt books which have a multiple-use sheet of carbon paper supplied, so that the user can keep an exact copy of each receipt issued, although even here carbonless copy paper is often used to the same effect.It is still common for a business letter to include, at the end, a list of names preceded by the abbreviation "CC", indicating that the named persons are to receive copies of the letter, even though carbon paper is no longer used to make the copies.
An alternative etymology is that "c:" was used for copy and "cc:" indicates the plural, just as "p." means page and "pp." means pages. This alternative etymology explains the frequent usage of "c:" when only one recipient is listed, while "cc:" is used for two or more recipients of the copies. This etymology can also explain why, even originally, "cc:" was used to list recipients who received typed copies and not necessarily carbon copies. Sometimes this "cc" is interpreted as "courtesy copy".