Daguerreotype

The Daguerreotype process involved combining metal particles and chemicals on a silver-covered piece of copper to reflect, or give back, images of light. This reflective process was able to produce sharp, colorless pictures.

The daguerreotype first made it possible to capture and save “true” images that presented a realistic look at history.

The team used X-ray technology to map and examine daguerreotype plates from the 19th century. The process is designed to identify the levels and position of mercury particles on the plates.

Researchers said the X-ray imaging process takes about eight hours on each daguerreotype plate. When complete, full images can be recovered, even if they could not be seen at all before.

The awakening of science to this new way of seeing the cosmos began with Johann Ritter in 1801. By 1815, scientists found that Ritter's “chemical rays” [ultraviolet rays] darkened not just silver chloride but also many other kinds of metallic salts. Between 1826 and 1837, Nicéphore Niépce, credited with taking the first successful photograph, in 1827, and Louis Daguerre, the most famous photographic innovator of his day, found that silver iodide was especially light sensitive, and they used this discovery as the basis for their early work, which even then had begun to gain international notice. By 1842, others found that when sunlight hit a gelatin emulsion containing silver iodide, soon to be called a daguerreotype plate, it induced a photochemical reaction. Practical photography was born.

[H]e scanned my countenance with a pair of fierce, blood-shot eyes that I knew would daguerreotype my appearance indellibly^([sic]) and faithfully upon his mind.