Is a term ordinarily applied to pictures, prepared with semi-transparent or translucent materials, and illuminated at the back, so as to exhibit them at night. The art of preparing them is as follows:-
The paper (or other material) must be fixed in a straining frame, in order to place it between the eye and the light, when required. After tracing the design, the colour must be laid on, in the usual method of stained drawings. When the tints are got in, place the picture against the window on a pane of glass framed for the purpose, and begin to strengthen the shadows with Indian ink, or with colours, according as the effect requires; laying the colours sometimes on both sides of the paper, to give greater force and depth of colour. The last touches for giving final strength to shadows and forms, are to be done with ivory-black or lamp-black prepared with gum-water, as there is no pigment so opaque and capable of giving strength and decision. When the drawing is finished, and every part has got its depth of colour and brilliancy, being perfectly dry, touch very carefully with spirits of turpentine, on both sides, those parts which are to be the brightest, such as the moon and fire; and those parts requiring less brightness, only on one side. Then lay on immediately, with a pencil, a varnish, made by dissolving one ounce of Canada balsam in an equal quantity of spirit of turpentine. Be cautious with the varnish, as it is apt to spread.
When the varnish is dry, tinge the flame with red lead and gamboge, slightly touching the smoke next the flame. The moon must not be tinted with colour. Much depends upon the choice of the subject. The great point to be attained is a happy coincidence between the subject and the effect produced. The fine light should not be too near the moon, as its glare would tend to injure her pale silver light; those parts which are not interesting should be kept in an undistinguishable gloom; and where the principal light is, they should be marked with precision. Groups of figures should be well contrasted; those in shadow crossing those that are in light, by which means the opposition of light against shade is effected,