Scanning electron microscope image of the lenticular array in the U.S. 100 dollar bill. The lenticular array,or micro-lens,shows a different colour when the viewing angle of the bill is changed. This is just one of the security (anti-counterfeit) features of the United States 100 dollar bill,others include: micro-print,watermarks,lenticular images,special inks,fluorescent fibers and strips,coloured fibers,and the use of full coloured inks. Image that 4 mm wide,and when printed 10 cm wide the magnification is 250x |