At the same time, some developed countries such as the USA, Germany and France began publishing their respective national catalogues of paper money, which represented major points of reference literature.
In 1961, The International Bank Note Society (IBNS) was formed as an international association of banknote collectors. Nowadays it has thousands of members from around the world. The IBNS publishes the quarterly IBNS Journal, holds regular mail bid auctions, and promotes lectures at congresses.
The major contributor to this study has been Albert Pick who published some of the earliest catalogues of paper money and through them explained the objective of collecting paper money and the definition of it. Albert Pick is also the author of the capital part of the Standard Catalog of World Paper Money, now a three-volume set which consists of thousands of pages of almost the entire collection of the world paper money that has ever existed and is updated annually. Almost every note of every country and many special and regional issues are cataloged following a unique format for each entry: [Country Name]P[unique number for the banknote edition]
So, we have something like: Yugoslavia P-117.
An important aspect of collecting banknotes is the condition of items. Banknotes that haven't been issued and circulated are rated as uncirculated (UNC) and that is the highest classification for a value that a banknote can have. In addition to that, the value for a specific note in the world paper money catalog is listed for UNC condition.
In addition to these grades, it is common to indicate an in-between grade, such as AU-UNC, which is a note that falls between AU and UNC, e.g., because has barely a noticeable counting fold.
Certain vendors and auctioneers break the UNC grade down further, into three grades.
Collectors will always prefer an Uncirculated note, and these notes command substantial premiums over lower grades. A note in UNC condition is generally worth up to ten times more in this condition compared with merely VG (Very Good). An UNC note can be worth three times as much as a VF one. For notes seldom found in uncirculated condition, the premium may be even higher. The difference between Gem Uncirculated and Uncirculated can also be substantial. As a result, buyers are at risk of grade inflation, in that a dealer failing to notice a fold in an AU note and passing it off as UNC will undoubtedly feel justified in charging a higher price.
Bank notes below VF are usually considered undesirable in a collection, and are generally purchased where better-quality examples are either unavailable due to their scarcity or simply beyond the collector's budget. Common notes in such poor condition, however, are effectively unsaleable for anything above their face value (assuming they are still legal tender).
Various third party grading company's (TPG) offer the service of authentication, grading and cataloging of common varieties of paper currency. These TPG's typically use a seventy-point grading scale to describe the note. Additional notations may be made for exceptional paper quality or other varieties.
Following examination, TPG companies typically encapsulate the currency in what is commonly referred to as a "slab." Similar to the issues surrounding the transition that occurred within the coin collecting field many years ago, controversy exists about the need or value of TPG notes. Without having the ability to closely examine and feel the note due to it being sealed inside the slab, many collectors are not comfortable accepting the opinion of others as to the grade and may either elect not to purchase the note or to cut it out of the slab for examination. Additionally, many noted mistakes in grading by third party grading services have been discovered. However, for collectors less adept at grading, purchasing a note in a slab can provide some additional comfort for the owner in justifying the purchase and cost. It also serves to help protect the collector against unethical activities designed to increase the worth of the note by pressing out folds, washing, repairing tears, or other alterations typically viewed as unacceptable thereby lowering the value of the item.
The vast majority of bank notes are sold using the Uncirculated-Poor grading system, and are never graded with any third party.
Postal order collecting has become a branch of notaphily, especially in England since the 1980s. Some countries, such as Basutoland, the British Somaliland Protectorate, and Northern Rhodesia never issued their own banknotes, but they did issue their own postal orders, however. Great Britain, the Isle of Man, and Northern Ireland also issued Old Age Pension Orders as well as postal orders. These have become collectible in recent years.
People collect paper money by: