Limestone Printing Block
Date: c. 1900
Description: This large printing stone contains the logos for three different Sioux City businesses: Mallory Commission Company, the Livestock National Bank, and Sioux Milling Company. (Sioux Milling was a grain milling company that processed and manufactured products from grain instead livestock, such as flour, grits, and the like. The other companies were involved in the meat industry.) It was made by the Perkins Brothers Company, owners of the Sioux City Journal. Before the invention of zinc printing plates, large stones like these were used. The text is made up of a special polymer that repels water. Once the text is applied, the stone is covered with an ink and water mixture. The ink is retained by the polymer and the water runs off. This was a much more efficient method than etching, in which text had to be carved in relief on stone, covered in ink, and pressed onto a page. This method saved the work of etching and allowed for longer and more detailed print runs.
Though we usually associate printing plates with newspapers, they were not the only businesses to use them. Many businesses, including many in the Sioux City stockyards, needed all manner of printing done, from letterheads, logos, checks, and other printed documents. These businesses also used printing plates for these documents, just as newspapers did. When zinc plates were developed a new process of pressing text into them called photoetching became easier and more efficient than printing on stone.
Donor: Sioux City Community School District