The two last chapters treated principally of the different modes of putting the chromolithographs subject upon the stones, and the means of securing their proper register. We come now to the printing of these stones, and shall first of all refer to the qualities of the colours without entering into the question of their harmonies, a subject which has been fully treated of by more competent authors.

169. The Pigments employed in Lithography embrace nearly the whole of those produced by the colour-makers, but they are not all equally suitable for lithographic printing. The two necessary qualities are permanency and ease of working, but these are possessed in quite different degrees by the different pigments. The following inexpensive works may be consulted with advantage:—“Hints on Colour and Printing in Colours,” by P. B. Watt. London: Wyman & Sons. “Colour,’ by Professor Church. Cassell, Petter, & Galpin. “The Principles of Colouring in Painting,” by Charles Martel. Windsor & Newton. Fortunately nearly all the most trustworthy pigments can be successfully used in printing, but some of the most brilliant ones are not only unpleasant in use, but fugitive in colour. This question of permanency of colour is either much misunderstood or not sufficiently attended to by many among the colour-printers of the present day. The demand for cheap inks is probably one great reason why so many of our productions fade so rapidly, and it is not in lithography alone, but in typographic blockprinting as well, that this defect frequently exhibits itself.