As a counterfeiter, Emanuel Ninger was as smooth as an Indian head nickel. He spurned the usual method of his day, circa late 1800s, of running off bogus bills on small presses. Instead, he hand drew each note, usually two a week, using only pen and ink.
The one-time German sign painter went 14 years before getting caught - and then on a fluke. He laid a bill on a wet counter one day and smudged the ink. Ultimately, though, Ninger may have gotten the last laugh: His Monet-quality money now fetches several thousand dollars per note.
Today's counterfeiters are less artistic but their results more profound. Close to $8 million in bad money was passed in the US last year. That represented a slight drop since 1982 - but was still nearly four times the amount of just 10 years ago.
Moreover, within the next few years new technologies will be entering the market - advanced color copiers and better printers - that could dramatically boost those numbers.
The threat is serious enough that the US Treasury is weighing a redesign of the trusty old greenback - unchanged since 1929 - to thwart would-be counterfeiters.
Nor is the US alone. Concern about counterfeiting is believed to be a root cause for several other countries' altering of currencies:
* Japan will be changing the look of some of its yen, using new faces and smaller notes, starting Nov. 1.
* Britain is considering altering its 20- and 50-pound notes.
* Australia, Canada, and West Germany may do the same within the next few years, too.
''Since 1970 almost every country in the world has changed its currency'' largely due to the threat of counterfeiting, says Robert Leuver, director of the Treasury's Bureau of Engraving and Printing.
The problem represents the dark side of innovation - and one that isn't limited to paper money. New technologies, from silkscreening machinery to laser scanners, are making it easier for forgers to copy documents. These range from identifications (social security cards, drivers' licenses) to financial documents (bonds, travelers' checks) to other tender (credit cards, food stamps).
Technology has been enlisted to battle technology. Credit card companies, for example, have embedded holograms and other devices in cards to thwart thieves. A new generation of card-reading machines is also being devised. Similar detection equipment has long been used to detect bogus money.
But pressure is building to make changes in the currency itself to counteract counterfeiters, given the high-tech threat on the horizon. The chief concern in this case is a new generation of color-copying machines now under development in corporate labs. They are capable of making good replicas of money, quickly. The fear is they could tempt a whole new cadre of crooks.
At present, counterfeiting is a complex chore, usually carried out by an organized group and requiring a significant capital investment. But by 1990, enough of these advanced copiers will be distributed in offices, quick-print shops, and other public places to bring the crime within the reach of stenographers and sales people.
Better offset printing equipment and computer graphics (used to design printing plates) pose problems, too, but not like the photocopiers. ''You are eventually going to get to the point where a guy has a $20 in his pocket, and he has a date, so he goes in and makes another $20,'' says Robert Snow, assistant director of the US Secret Service, the agency charged with stopping counterfeiting.
The Treasury is considering three different changes in US currency to halt the problem. Any redesign would be minimal, says Mr. Leuver. Since the dollar is an international currency, a dramatic change could cause confusion. That means the greenback will remain green, and the familiar portraits will continue to peer out from the front.
One option is to add color patterns to the white spaces on the front of the notes. Subtle tints would be used, since the new copiers reproduce vivid colors well. Another approach is to embed an ''optical variable device'' on the bill, such as a hologram or thin film, that results in a 3-D image or different colors appearing when the note is tilted. The third alternative is to weave a small Mylar plastic thread into the paper. The thread could be seen if held up to a light. When photocopied, it would appear black.
One added advantage to the security thread: magnetically encoded bits of information could be stored on them, aiding, for instance, banks with their money sorting. But this potential also worries some critics who see the possibility of an invasion of privacy. What, for example, is to stop the government from using encoded data to trace currency in circulation or monitor consumer behavior? Treasury officials, however, insist nothing nefarious is intended.
A decision on whether to redesign is expected within the next year. If the Treasury gives the nod, new bills could begin showing up in wallets and purses as early as 1986. Most experts believe any one of the three changes would offset the new counterfeiting threat. They could also as much as quadruple the cost of printing money.
Undoubtedly, thieves will find other new tools in the future. But this doesn't necessarily mean that paper as a form of money is threatened. After all, points out Murray Teigh Bloom, a writer and currency expert, ''paper money has turned out to be the cheapest and most effective type of transaction material ever devised.''