Chromolithography is a method for making multi-colour prints. This type of colour printing stemmed from the process of lithography, and it includes all types of lithography that are printed in colour. Lithographers sought to find a way to print on flat surfaces with the use of chemicals instead of relief or intaglio printing. Chromolithography became the most successful of several methods of colour printing developed by the 19th century. The initial technique involved the use of multiple lithographic stones, one for each color, and was still extremely expensive when done for the best quality results. Depending on the number of colors present, a chromolithograph could take months to produce, by very skilled workers. To make an expensive reproduction print as what was once referred to as a “’chromo’”, a lithographer, with a finished painting in front of him, gradually created and corrected the many stones using proofs to look as much as possible like the painting in front of him, sometimes using dozens of layers.