Chromolithography is a method for making multi-color prints using stones or metal plates – based on the fact that oil and water do not mix.
The lithographic process is chemical, because an image is applied to a porous limestone or zinc plate with a grease-based crayon or ink. After the image is drawn onto stone, the stone is coated with a gum arabic solution and weak nitric acid, and then coated with water and inked with oil-based inks. Paper is placed on the inked image and run through a printing press to transfer the image to the paper using pressure.
Alois Senefelder discovered lithography in 1798, and it was monochromatic. Its name is based on “lithos” for stone and “graphien” for writing. It allowed images to be reproduced — anything that could be drawn on the stone would do.
Colors were later printed by drawing the area for each color on a different stone, and then printing the new color onto the paper. Each color in the image must be separately drawn onto a new stone or plate and applied to the paper one at a time. It was not unusual for 20 to 25 stones to be used on a single image. Each sheet of paper will pass through the printing press as many times as there are colors in the final print. Each print for each stone or plate had to be precisely registered, or lined up using register marks. This was not easy with manual methods.
Many of the images were embossed to add dimensionality.
Chromolithography could take months to produce. During the Victorian era, chromolithographs populated children’s and fine arts publications, as well as advertising art, in trade cards, labels, and posters. They were also used for advertisements, popular prints, and books with pictures. Many were printed to go into scrapbooks.