(Oklahoma City-AP) -- New five and ten dollar bills should begin circulating in Oklahoma on Wednesday.
Trisha Thompson is public affairs spokeswoman of the Oklahoma City branch of the Federal Reserve. Thompson says the new money will have more security features including color shifting on the tens.
Color shifting means the number in the lower right hand corner of the ten dollar note appears green but shifts to black when adjusted to the angle of light.
Thompson says the new five dollar bill won't have colorshifting ink because it's such a small denomination, it's not counterfeited enough to justify the cost.
The new fives and tens also have a larger portrait, a watermark and color security threat in the note.
Thompson says the move to make U-S currency more difficult to counterfeit is working. Counterfeiting is down nationally and worldwide.