Carbon copy

Carbon copying, often abbreviated to c.c., is the technique of using carbon paper to produce several copies of paper documents. On an old-fashioned typewriter, this would be done by placing the carbon paper between two sheets of paper in the machine, so that whatever was typed on the front sheet was copied onto the second sheet. This technique applies to written documents as well.

This practice declined with the advent of photocopying and other electronic means, although it is still used in some contexts; for example, manual receipt books commonly have a sheet of carbon paper supplied, in order that the user can keep an exact copy of each receipt issued.

However, the term "carbon copy" has found renewed use with the growth of the Internet, even though its original meaning does not apply. In the context of email, it refers to the practice of sending a message to multiple recipients. It is commonly used in mailing lists.

The CC addresses, however, are not hidden from the recipients, and this may not be a desirable thing, depending on the situation. To circumvent this, the header field BCC or blind carbon copy was created. In common usage, To field recipients are the audience of the message, CC field recipients are others whom the author wishes to publicly inform of the message, and BCC field recipients are those surreptitiously being informed of the communication.