Nathaniel Currier and James Ives were lithographers who joined forces in 1857. The lithographs (also known popularly as "prints") were printed in black and white and then hand colored by an assembly line of girls. Each girl was responsible for one color and they had to work fast to keep production numbers up. Various renowned artists of the day were used to create images of every phase of American life and history of the period. Currier retired in 1880 and died in 1888. Ives died in 1895. The original records of the firm have never been found and no one knows how many subjects were done or how many of each subject were made. Several of the later subjects would be considered politically incorrect by today's standards.