Storing data as mixtures of fluorescent dyes -—As the world's data storage needs grow, new strategies for preserving information over long periods with reduced energy consumption are needed. Now, researchers reporting in ACS Central Science have developed a data storage approach based on mixtures of fluorescent dyes, which are deposited onto an epoxy surface in tiny spots with an inkjet printer. The mixture of dyes at each spot encodes binary information that is read with a fluorescent microscope.

Seminal Michael Faraday paper digitally stored in fluorescent dyes. The dyes are cheap to make, but they can't be read without a special microscope.