Counterfeiting of bank notes, passports, identity cards and other valuable products is expected to become more complex and difficult with the rise of Nano Dot Printing. Using metal nanostrcutures instead of regular dyes to produce colors, Nano Dot Printing results in the highest print resoutions to date of up to 100,000 dots per inch (DPI), as opposed to an appromiate 1,000 DPI produced by conventional printers. being metallic, the prints will not fade with time. Read more about it on Nature Communications.
You can find more details at https://www.sutd.edu.sg/Research/Research-News/2012/7/Nano-Dot-Printing