Syngraphics is the study and collection of paper money. This branch of numismatics may not be as well known as coin collecting, but it is in fact quite a lively aspect of the greater currency-collecting community, and individual samples of paper money have sometimes fetched high prices at auction due to rarity or unusual circumstances. Several individuals in the numismatics field specialize in syngraphics.
This term was coined in 1974 by Gene Hessler, a specialist in syngraphics. He borrowed the concept from the idea of a syngraph, a contract to pay which is signed by all parties involves. In a sense, paper money is a form of syngraph, a signed contract from the government or issuing authority, as paper money has no inherent value, and in many cases paper money isn't even backed by a precious metals standard anymore, making its worth even more ephemeral.
Someone who specializes in syngraphics typically accumulates a large collection of paper money, which may be from a specific region or time period, or it may span multiple regions and eras. Because paper money is more subject to decay that metal coin, it must be well cared for in order to survive, and syngraphics specimens are typically of a more recent vintage than many collector's coins. In addition to a collection of physical currency, guidebooks may also be kept on hand to evaluate new specimens.
Just like coins, paper currency can have value for a number of reasons. Currency issued by a country which no longer exists is often valuable as a collector's item or item of general interest, for example, as is paper money which was only produced in a limited quantity. Currency with printing errors such as misregistration can also be valuable simply because it is unusual. Someone who studies syngraphics can determine the value of a specimen of currency brought to him or her for evaluation, and some specialists can also make preservation recommendations to ensure that the money is kept as pristine as possible.
In addition to being a commercial field, syngraphics is also studied at museums and in forensic laboratories. Museums may rely on syngraphics to authenticate samples of paper money on display, and they utilize numismatics research to learn more about the cultures and regions they study. In forensics, syngraphics can be used to determine whether or not money is counterfeit, and to learn more about the origins of physical currency involved in criminal cases.