Take a piece of best quality white tissue-paper, moisten it slightly, and paste it at the edges to the glass side of the negative. Moistening the paper before attaching it to the negative causes it to adhere closely to the glass without wrinkles. Put the negative in the retouching-frame with the glass side uppermost, and with a pencil go over the negative, softening the high lights, working up detail in the shadows--in fact, making a drawing of the negative on the piece of tissue-paper with which it is covered. When the drawing or pencilling is finished, take a crayon stump and blend the lines and lighten the edges of the shadows. It is a good plan to have a print of the picture pinned to the board as a guide to working on the negative. When finished and ready for printing, place a piece of tissue-paper or a sheet of ground glass over the frame, and print in the shade. If the first work is not successful, the paper can be removed and a fresh one substituted. Instead of using tissue-paper the back of the negative may be coated with ground-glass substitute, tinted with red or purple aniline dye. Ground-glass varnish may be made by the following formula, or may be bought ready prepared: Gum-sandarach 45 grains. Gum-mastic 10 grains. Ether 1 fluid ounce. Benzole 3/4 fluid ounce. Flow this over the back of the negative, and when dry it may be worked on with a pencil in the same manner as described for the tissue-paper. Where the solution covers the high lights it can be removed either by scraping it away and leaving the glass clear, or it may be removed with spirits of turpentine. The edges may be softened so as to remove the harsh contrast between the clear glass and the tinted solution by rubbing them with a powder made of one part finely powdered resin and two parts dextrine. A leather stump dipped in the powder is the best means of applying it. In landscapes, where in order to obtain prints of the clouds in the sky the other parts of the picture must be very much over-printed, apply the ground-glass solution to the back of the negative, and soften the lines where the horizon meets the sky by the dextrine powder. A few drops of the aniline dye will be sufficient to give the varnish a tint. Benzole is highly inflammable, and must not be brought near a light. The varnish should be kept in a glass-stoppered bottle, as the ether is volatile, and soon evaporates if not tightly corked. For blocking out backgrounds use Gihon's opaque, a non-actinic water-color paint. It costs fifty cents a cake, and one cake will last for a year or more.