The US Government is issuing new $5 and $10 notes today, as part of an increased effort to guard against counterfeiting measures.

Banks will begin receiving shipments today, but the general public probably won't see the bills for another week or so, depending on the current supply of $5s and $10s in the bank's vaults.

The bigger portraits of Lincoln and Hamilton, the nation's first treasury secretary, are easier to recognize, while the added detail make the currency harder to duplicate. Moving them off center makes room for a watermark and reduces wear on the portraits.

Other new features unveiled last year include: watermarks that are visible when held up to a light; embedded polymer security threads that glow blue on the new $5 bill and orange on the new $10 bill when exposed to an ultraviolet light; and very tiny printing, visible with a magnifying glass.

The Treasury reports that there are no plans to revamp the $1 bill.