<Li> Color - shifting ink that changes from green to black when viewed from different angles . This feature appears in the numeral on the lower right - hand corner of the bill front . </Li> <Li> Microprinting in the numeral in the note's lower left - hand corner and on Benjamin Franklin's coat . </Li> <Li> Concentric fine - line printing in the background of the portrait and on the back of the note . This type of printing is difficult to copy well . </Li> <Li> The value of the currency written in 14pt Arial font on the back for those with sight disabilities . </Li>

When was the dollar no longer backed by gold