Coming to cash registers near you: colorful new $50 bills sporting splashes of red, blue and yellow.

The bills, the second denomination of greenback to get the color treatment, were going into circulation on Tuesday as part of the government's continuing effort to thwart counterfeiters.

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

The Bureau of Engraving and Printing (search) has printed 140 million new $50s, the bureau's director, Thomas Ferguson, said in an interview. Many of the new notes have been shipped to Federal Reserve (search) banks, suppliers of the nation's cash, he said.

"The new $50s are going to be coming out gradually. The old ones are still very secure and will continue to circulate and be worth their full face value," Ferguson said. "The new $50 is a little bit more colorful, a little bit more patriotic and I think people are really going to like it."

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 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.