美鈔60年來皆未重新設計，聯邦鑄印局現在開始進行一系列美鈔的改頭換面工作，最新的設計是百元大鈔增加防偽安全線，目前這項工作已完成了三分之一，新的百元大鈔預期在明年底推出。

修改百元大鈔部分是為防止偽鈔，製造偽鈔者現在有更精密的電腦、掃描器和彩色影印機。正面為富蘭克林總統(hc ???)像的百元大鈔是海外偽鈔作業最常偽造的鈔票。

由微小形象組成的新安全線，性能有如出自「哈利波特」霍格維茲魔法師學校的魔術，但它是數十年研究的成果，結合了微縮印刷和微小透鏡，一張百元大鈔上有 65萬個微小透鏡，這些透鏡以非常神奇的方式把微縮印刷放大，若把百元大鈔左右移動，微縮印刷的形象會上下移動，把百元大鈔上下移動，形象會左右移動。

獲得4600萬元合約生產這些新安全線的克蘭公司副總裁克蘭(Dou-glas Crane)說：「那是一種顯微鏡規模的複雜光學結構，產生令人驚歎的高度安全設計。」

從1929年到一九九○年代中期，美鈔幾乎沒有重要改變，但為了防止偽鈔，鑄印局決定每七至10年重新設計鈔票，在一九九○年代中期開始增加第一輪的安全 特色，2003年開始，20元和其他面值的鈔票開始增加顏色，但百元大鈔的改變拖至最後，因為政府在尋找高度安全的設計，以對此鈔票提供最大的保護。百元 大鈔在目前通行的7760億元貨幣中占超過70%，其中三分之二是在海外。

百元大鈔採用的安全線也被瑞典的千元克朗和墨西哥的高面值鈔票採用。

【2007/08/27 世界日報】

Currency change aimed at adding security

By MARTIN CRUTSINGER, AP Economics Writer Sun Aug 26, 12:44 PM ET

WASHINGTON - After six decades in which the venerable greenback never changed its look, the U.S. currency has undergone a slew of makeovers. The most amazing is yet to come.

A new security thread has been approved for the $100 bill, The Associated Press has learned, and the change will cause double-takes.

(double take
n.

A delayed reaction to an unusual remark or circumstance, often used as a comic device.)

double take　（喜劇役者が）初めはうっかり聞いて笑っているが途中で気がついてぎょっとする仕草.

The new look is part of an effort to thwart counterfeiters who are armed with ever-more sophisticated computers, scanners and color copiers. The C-note, with features the likeness of Benjamin Franklin, is the most frequent target of counterfeiters operating outside the United States.

The operation of the new security thread looks like something straight out of the Hogwarts School of Witchcraft and Wizardry. This magic, however, relies on innovations produced from decades of development.

It combines micro-printing with tiny lenses — 650,000 for a single $100 bill. The lenses magnify the micro-printing in a truly remarkable way.

Move the bill side to side and the image appears to move up and down. Move the bill up and down and the image appears to move from side to side.

"It is a really complex optical structure on a microscopic scale. It makes for a very compelling high security device," said Douglas Crane, a vice president at Crane & Co. The Dalton, Mass-based company has a $46 million contract to produce the new security threads.

Larry Felix, director of the Bureau of Engraving and Printing, confirmed details about the security thread in an AP interview.

The redesign of the $100 is about one-third of the way complete. The bill is expected to go into circulation late next year.

Starting in 2003, splashes of color have spruced up the $20 bill and other currencies. Those changes followed the addition of a first round of security features in the mid-1990s.

Benjamin Franklin's latest makeover was delayed while the government searched for a high-tech security device that would provide extra protection on the bill.

The $100 bill represents more than 70 percent of the $776 billion in currency in circulation, two-thirds of which is held overseas.

Holograms, used extensively on credit cards, were considered for the $100. They were rejected because they did not offer the strong visual signal the government wanted.

"We were looking for features that had very distinctive types of actions so that we could tell the American public, you will know that it is authentic if you do this and the note does that," Felix said.

The new security thread is used on the Swedish 1,000 kroner note and has been selected by the government of Mexico for some higher denomination notes.

Felix said many other devices expected to be included in the $100 redesign will be similar to features added over the past four years to the $20, $50 and $10 bills. That means subtle pastel colors on the currency and patches of micro-printing that are difficult to duplicate, along with a touchup on Ben Franklin's portrait.

Originally there were no plans to redesign the $5 bill. That decision was reversed once counterfeiters started bleaching $5 bills and printing fake $100 bills over the bleached paper; certain security features were in the same location on both bills.

The new $5 design will be made public on Sept. 20 and will go into circulation early next year.

The bleached bills represent the latest skirmish in a battle with counterfeiters.

"Counterfeiting is becoming highly organized and highly efficient," Felix said. He said some clandestine printing plants in Latin America and Eastern Europe have been caught counterfeiting not only the U.S. currency but other countries' notes.

The government says $118.1 million in counterfeit U.S. currency was detected in 2006, an increase of 3.8 percent from 2005.

While that is a fraction of the currency in circulation, the Secret Service is concerned with the threat, especially the challenge posed by new digital technology. Digital copies account for about half of all counterfeit notes passed in the U.S., compared with less than 1 percent of all counterfeit bills detected in 1995.

"The quality of the counterfeit currency has gone down, but the ease by which people can make this currency and the access to the computer equipment has had an impact on the rising numbers," Secret Service spokesman Eric Zahren said.

To stay ahead of the counterfeiters, the Bureau of Engraving and Printing plans to redesign U.S. currency every seven years to 10 years. That is a far cry from the practice for most of the 20th century — from 1929 to the 1990s — when the currency stayed the same without any major changes.

"We had three generations of engravers who spent their entire careers at the bureau and never saw their designs hit the streets," Felix said. "Now since 1996, we have all of these changes."

All the new security devices have added to the complexity of making money. The government churns out 38 million notes each business day with a face value of $750 million at two facilities — one in Washington, D.C., and the newest one in Fort Worth, Texas.

By order of Congress, the $1 bill, which accounts for 45 percent of the notes printed each year, will not be redesigned. Lawmakers were concerned about the cost to business if low-end vending machines that only take coins and $1 bills had to be upgraded.

In addition to redesigning the money, the bureau is putting in new printing presses with more capabilities to handle the increasingly sophisticated security features.

The new presses can vary the size of the bills being printed. That is something the American Council for the Blind is urging the government to consider as a way of helping the visually impaired distinguish between different denominations of currency.

Felix says no decision has been made on such a change. The government is appealing a federal court ruling that could force such a redesign.

In its continuing effort to stay ahead of counterfeiters, the bureau is reviewing a wide range of new ideas such as adding a sense of depth to the designs.

"Currency is essentially a confidence situation," Felix said. "You have to always stay ahead in changes."

___

On the Net:

Bureau of Engraving and Printing: http://www.moneyfactory.gov

A history of U.S. currency from the Federal Reserve Bank of San Francisco: http://www.frbsf.org/currency/index.html