The genuine portrait appears lifelike and stands out distinctly from the background. The counterfeit portrait is usually lifeless and flat.
Details merge into the background which is often too dark or mottled.
Federal Reserve and Treasury Seals
On a genuine bill, the saw-tooth points of the Federal Reserve and
Treasury seals are clear, distinct, and sharp. The counterfeit seals may
have uneven, blunt, or broken saw-tooth points.
The fine lines in the border of a genuine bill are clear and
unbroken. On the counterfeit, the lines in the outer margin and
scrollwork may be blurred and indistinct.
Genuine currency paper has tiny red and blue fibers embedded throughout.
Often counterfeiters try to simulate these fibers by printing tiny red
and blue lines on their paper. Close inspection reveals, however, that
on the counterfeit note the lines are printed on the surface, not
embedded in the paper. It is illegal to reproduce the distinctive paper
used in the manufacturing of United States currency.