Noun
a thin paper coated on one side with a dark waxy substance (often containing carbon); used to transfer characters from the original to an under sheet of paper
Source: WordNetcarbon-paper
After more standardized ballots were introduced, these practices continued, applying methods such as requiring voters to use carbon paper to record their vote publicly in order to be paid. Source: Internet
It is usually made of platinum powder very thinly coated onto carbon paper or cloth. Source: Internet