“It will be noticed that practically every tone is a separate shape, put down with the right pressure, and, if possible, not gone over twice, or else the lead becomes shiny and will not mark in the darks ; and if the shading is worried the quality and spontaneity of the handling will be lost. Before attempting this method of shading, one should practise the scale for the necessary pressure of the lead or touch required to mark the different intensities of shades and shapes.”