FIFTEENTH STONE—LIGHT RED.
SIXTEENTH STONE—DARK GREY.
Having described the manner in which the picture on stone is prepared, we now come to the printing of it. To begin with, there is the "proving-press," which is employed in preparing the stones for the machine. The gummy solution is first washed off, but sufficient remains in the pores of the stones to offer a resisting influence to the ink when the time for printing comes. At this stage the stone is damped and a roller charged with printing ink is passed over its surface, every part of the design being brought in contact with the ink. Accidental grease spots are removed by scraping, polishing, or the application of acid, otherwise they would develop and spoil the result.
SEVENTEENTH STONE—GOLD.
EIGHTEENTH STONE—LIGHT GREY.