Coming to cash registers near you: Colorful new $50 bills sporting splashes of red, blue and yellow. Next up for a makeover, the government said Tuesday: $10 bills.

That would bring to three the number of greenbacks to undergo the color treatment in an effort to thwart counterfeiters.

The new $10 is expected to be unveiled this spring and put into circulation in fall 2005, Thomas Ferguson, director of the Bureau of Engraving and Printing (search), said in an interview.

Alexander Hamilton (search), the nation's first treasury secretary, is expected to stay on the front of the new $10 with the Treasury Department (search) on the back, officials said. Various efforts have emerged to put former President Ronald Reagan (search) on the nation's currency, either on the $10 bill or the $20 bill, or possibly the dime.

The new $50s went into circulation on Tuesday and soon will be showing up at banks, cash registers and wallets. Ferguson said that 140 million of the new $50s have been printed.

Ulysses S. Grant (search), the Civil War general and 18th president, remains on the front and the U.S. Capitol remains on the back of the new bills. But subtle colors have been added — joining the traditional black ink on the fronts and green ink on the backs. The design for the new $50s was unveiled in April.

Old $50 bills will continue to be accepted and recirculated until they wear out.

After the $10 makeover comes the $100 bill, the most counterfeited note outside the United States, Ferguson said. The $5 bill won't get a new look, neither will the $1 and $2 notes, he said.

Colors for the redesigned notes vary by denomination. Ferguson didn't say what the colors would be for a new $10 and a new $100.

A new $100 note was supposed to follow the new $50 but that changed because the bureau is considering additional security features for the $100 bill. A timetable for a new $100 bill introduction hasn't been set.

Security features include an embedded thread that glows yellow when exposed to an ultraviolet light; ink that changes color — from copper to green — when the note is tilted; watermarks visible when held up to light; and hard-to-replicate microprinting. In one spot, the tiny words "United States of America" appear on Grant's collar, under his beard.

Old $50 bills will continue to be accepted and recirculated until they wear out.

The $20 bill, the most counterfeited note in the United States, was the first to get extra color. Featuring touches of peach, blue and yellow, the new $20 went into circulation last fall. The colorizing project is part of a larger makeover of U.S. currency aimed at thwarting counterfeiters.

The government has launched an extensive campaign to help people, especially those who handle cash frequently in their jobs such as merchants and bank tellers, to be able to spot genuine versus bogus bills.

Moreover, the government has worked with industry to make appropriate changes so that various machines, including vending machines, fare-card machines, self-checkout equipment used by some grocery and home-supply stores, will accept the new notes.