Even with the most transparent paper it occurs that certain delicate drawings, and especially color pictures, will not show through sufficiently. Then the drawing must be fastened to a window pane to obtain added illumination. This manner of work is very uncomfortable, however, and the arms hurt one soon, so that it is necessary to stop. It is better to have a tracing-board made with a strong, clear pane of glass in the centre. Under it is a mirror so adjusted that it reflects light upward through the drawing. It is understood, of course, that in tracing only the outlines are copied and not every stroke of shading, etc. Although the final work is greatly facilitated by the observation of the utmost care in tracing, the tracing of every little detail will merely make the work involved and perplexing. Practice must show the proper degree of exactness. A very good and skillful artist often needs only a few main outlines, to reproduce the original picture with the greatest accuracy. Once the drawing has been traced sufficiently, the transfer paper must be coated very lightly and evenly with red chalk. Then it is fastened to the stone with wax and all the lines are traced under moderate pressure with a well-polished needle whose point is not sharp but rounded. Where the needle presses the tracing-paper, the color that is on the other side will take hold of the stone and thus transfer the drawing to it. If the needle is too sharp, it will injure the paper, and often the stone and the etching surface. The color on the paper must be rubbed off very carefully with a soft rag. If it is too thick, it will transfer itself coarsely to the stone. The red chalk may be put on the side of the paper that has the drawing on it, or on the reverse. This is decided according as the picture is to be on the stone in the same position as the original or reversed. If the impression is to be like the original, the drawing on the stone must be reversed; therefore in that case the tracing-paper is coated on the same side as the drawing. This side is laid on the stone, and the picture, which shows through, is traced. In some cases it is good to transfer the drawing from the tracing immediately to the stone without tracing it with the needle. In this case, the paper is not coated with red chalk. The paper is merely laid on the prepared stone, drawing face down, and put through the press. If the drawing has been made with the chemical transfer ink, blackened with lampblack or colored with vermilion according to need, it will transfer itself to the stone. This will occur also in the case of a clean stone prepared for pen drawing if the drawing is made with lead pencil or with red chalk, wet or dry. Even the ordinary ink made from nutgall and vitriol of iron will transfer if it contains a little sugar or gum, but the paper must be well dampened and good pressure must be applied to the press.