Portrait Orientation: Bills printed before 1996 had a vertical (portrait) orientation. The $1, $2, $5, $10, $20, $50, and $100 notes all featured the portrait of a prominent historical figure facing the viewer. After 1996, the U.S. Bureau of Engraving and Printing switched to a horizontal (landscape) orientation for new bills for easier processing by automated currency-handling machines.
Different Color Palettes: Bills printed before 1996 generally had a more muted and varied color palette. For example, the $1 was light brown, the $2 featured purple and navy colors, the $5 was gray and black, and the $10 had tints of orange and yellow. With the 1996 redesign, the new钞票adopted more vibrant and distinct colors to aid in quick identification and counterfeit detection.
Different Security Features: Prior to 1996,钞票incorporated various anti-counterfeiting measures, but they were less advanced compared to the features on current notes. Older bills incorporated security threads and watermarks; however, the threads were relatively simple woven fibers embedded within the paper. With the redesign,钞票began utilizing enhanced security threads with microprinting and other intricate details. Modern security elements like color-shifting ink, microprinting, and fluorescent elements were also introduced.
Different Material Composition: Bills printed before 1996 were manufactured using 100% cotton fiber paper. This natural fibers composition gave the钞票a characteristic crisp and sturdy feel. In 1996, the U.S. Bureau of Engraving and Printing introduced a cotton-linen blend material for钞票which enhanced their durability and longevity. The newer composition, approximately 75% cotton and 25% linen, resists deterioration better from daily use and handling.
Overall,钞票printed before 1996 are still valid for their face value, but they are no longer in general circulation. The redesigned currency introduced in 1996 aimed to incorporate enhanced security features, improve durability, and facilitate efficient processing of钞票through automated systems.