This image is an early example of a scientific fundamental of photography--the light sensitive nature of certain chemical compounds. Without the use of a camera or lens, Hippolyte Bayard carefully arranged a delicate selection of laces and flora on a sheet of paper that was made sensitive to light with a combination of iron salts that produced a blue-toned cyanotype when developed. The sheet of sensitized paper with the objects placed upon it is exposed to sunlight in order to make a camera-less photogenic drawing.
The opacity of the object blocks the light in relation to its density, thus creating a silhouette of the object on the paper. Because the process was relatively uncomplicated, cyanotypes provided a quick method of recording easily recognizable shapes and patterns. Bayard filled the entire sheet of paper, creating a catalog of specimens that reveals the basic structure of each flower, leaf, feather, and scrap of fabric.