04.

Emanuel Goldberg (in 1925) actually perfects the technology for making microdots, doing so by using a luminous projector that passes light through a Zeiss microscope fitted with specially corrected lenses, all mounted on an optic bench (cushioned against ambient, seismic vibration), with the image developed on a brass plate coated in a sensitive collodion emulsion of silver chloride and citric acid.³ Goldberg first makes a microdot that depicts a cameo of Nicéphore Niépce (the pioneer of photo-graphy), but eventually Goldberg prints small texts with letters, one micron in size— a resolution equivalent to the microscopic inscription of fifty Bibles per square inch. His techniques drive subsequent innovation in micrography — the modern limits of which include the tunnelling microscope, whose scans can map the contours of a lone atom of hydrogen.