Carbon paper
Carbon paper (originally carbonic paper) is paper coated on one side with a layer with a loose ink or pigmented coating.
Carbon paper is placed between the original and a blank sheet to be copied onto. As the user writes or types on the original, the depressions made cause the ink to be deposited on the blank sheet, thus creating a "carbon-copy" of the original document.
Use of carbon paper has been mostly superseded because of electronic means such as photocopying. However, a carbonless copy paper is still used in situations where instant copies of written documents are needed. Examples of this are receipts at point of sale or for on-the-spot fine notices.