How To Tell If 100 Bill Is Real. If the mark turns dark brown or black, then you know the bill is fake. A watermark bearing the image of the person whose portrait is on the bill can be found on all $10, $20, $50, and $100 bills series 1996 and later, and on $5 bills series 1999 and later.
When looking at older $100 bills the foil strip should include those same small numbers and a maple leaf that changes colour when tilted. The $100 bill has a colored number stretching vertically from corner to corner on the back. You get a marker or highlighter and put a dash on the dollar bill, if the marker changes colors its fake or fold the left side of the dollar bill about 1/4 the way in.
