In the first half of the 19th century, color images were usually printed in black and white and then colored by hand.
Chromolithography, a technique for printing in colours, began to be employed to print color images in the 1840s. It had a dazzling and meteoric life. After centuries of black ink on white paper, it burst onto the printing scene about 1840 and then vanished by the 1930s. But during this nearly one hundred year period, it revolutionized the printing industry and captivated the world with colourful hues.
An image would be drawn with a grease pencil or greasy ink onto a flat, porous surface such a stone or a metal plate. The image would be affixed to the plate with an acid bath. The plate would be coated with an ink mixture which adhered only to the greasy portion of the surface, sitting atop the flat surface of the printing plate. Typically, individual colors in the illustration would need their own plates.
Chromolithography appealed to the Victorians and their great love of colour.