the late twentieth century, advances in computer and photocopy technology made it possible for people without sophisticated training to copy currency easily. In response, national engraving bureaus began to include new, more sophisticated anti-counterfeiting systems such as holograms, multi-colored bills, embedded devices such as strips, raised printing, microprinting, watermarks, and color-shifting inks whose colors changed depending on the angle of the light, and the use of design features such as the "EURion constellation" which disables modern photocopiers. Software programs such as Adobe Photoshop have been modified by their manufacturers to obstruct manipulation of scanned images of banknotes. There also exist patches to counteract these measures. Recently, there has been a discovery of new tests that could be used on U.S. Federal Reserve Notes to ensure that the bills are authentic. These tests are done using intrinsic fluorescence lifetime. This allows for the detection of counterfeit money because of the significance in difference of fluorescence lifetime when compared to authentic money. For U.S. currency, anti-counterfeiting milestones are as follows: 1990 Microprinting and a security thread are introduced on U.S. currency 1996 $100 bill gets a new design with a larger portrait 1997 $50 bill gets a new design with a larger portrait 1998 $20 bill gets a new design with a larger portrait 2000 $10 bill and $5 bill get a new design with a larger portrait 2003 $20 bill gets a new design with no oval around Andrew Jackson's portrait and more colors 2004 $50 bill gets a new design with no oval around Ulysses S. Grant's portrait and more colors 2006 $10 bill gets a new design with no oval around Alexander Hamilton's portrait and more colors 2008 $5 bill gets a new design with no oval around Abraham Lincoln's portrait and more colors 2010 $100 bill gets a new design with no oval around Benjamin Franklin's portrait and more colors; along with the inclusion of the new "3D security ribbon" The redesigned $100 bill was unveiled on April 21, 2010, and the Federal Reserve Board was to begin issuing the new bill on February 10, 2011, but the release was delayed due to printing problems until October 2013. The Treasury had made no plans to redesign the $5 bill using colors but recently reversed its decision after learning some counterfeiters were bleaching the ink off the bills and printing them as $100 bills. The new $10 bill (the