Printing Trade Cards
This unusual set of six cards promoting Liebig Meat Extract illustrates the manner in which trade cards were produced by a nineteenth-century color-printing method called chromolithography. This method uses the flat surface of specially prepared stones as printing plates. Chromolithographic images are produced by printing each color separately, then superimposing those colors to make a finished full-color print. The process is labor-intensive, as each color requires a separate stone with the image (or portion of the image) drawn on it. The stones are then inked individually, and until the invention of modern presses, the paper—one sheet at a time—was run across the stones, taking on each pass the impression of a different color.
These cards demonstrate the chromolithographic process. Ingeniously, they depict both the steps in the process and the manner in which a printed image is formed, one color at a time. The image in this case is a cameo portrait of Justus von Liebig, whose product is being advertised, reproduced using twelve individual ink colors, each laid down in a separate pass through the printing press; the gold frame requires a thirteenth pass. The number of colors used in this example is unusually high, the norm for nineteenth-century trade cards being five or six colors. An interesting footnote to this series of cards is the presence of women workers in the printing plant.
