The imitation of marbles differs materially from that of woods inasmuch as, in the case of woods, it is usual to do the greater part of the work in glazes applied in water color; whereas the nature of marbles demands a more solid and opaque treatment.
Consequently, marbling is almost entirely executed in paint and in body colours. Glazes are used to add depth and translucency where required, and water colour is sometimes used for the sake of its rapid drying.
White Marble. The simplest marble to execute, and at the same time one of the most difficult to imitate faithfully, is white or Sicilian marble. The ground required for this marble is a dead white. When the ground is dry and hard, a thin coat of zinc white in oil is rubbed over it, and the veins are put in with a crayon ; a warm grey crayon is used for the inner veinings, and a soft black lead pencil or black conte crayon for the more prominent ones. The spaces between the veins are then tinted slightly with grey and green, and a few touches of yellowish grey, all very sparingly used, and the whole softened with the hog hair softener.
Sienna Marble. Sienna marble is next in importance, and is much used for columns, pilasters, and staircase walls. The same ground is used as for the white marble, and while this is still wet it is irregularly painted with two or three tints of yellowish cast, made from white and raw Sienna. The veins are then put in either with a black crayon or charcoal, or a soft lead pencil, and softened into the ground. When this is dry, additional shadows, &c., are glazed in in raw Sienna and burnt Sienna, and the veins are emphasised with a little blue or lake. Over all a few white veins or spots are run, and a few lights put on in the interstices between the dark veins.
Italian pink marble is used in place of Sienna, and is about the same depth of tone, but pink, as its name implies. The ground required is the same as above. The ground is scumbled over with pink, made from ochre and Venetian red, and ochre and vermilion, and shaded in with greyer tones. The veins are put in with purplish red, and the whole blended and softened with the hog-hair softener. After all, a few white veins crossing the deep ones, and a few blotches of white, with here and there rose pink glazings, are added.
Black and gold is a popular marble for skirtings, and string courses, chimney pieces, &c. The ground is black. The larger veins are a gold colour made from ochre and red, and may be varied, in colour indefinitely ; they are put upon a dry ground with a pencil and oil colour. Very fine distinct white and yellow veins run from the main ones, splitting up the black ground into fragments. The black spaces are then shaded and lightened by the use of grey tints. A few particles of gold leaf or metal put into or upon the gold colour veins improve the effect. Another method is to work in Sienna upon a white ground, and badger and blend various golden red and yellow hues together, to allow this to dry and then to paint in the intervening spaces with black and grey. The peculiarity of this marble is the intricate ramifications of the veining.
Grey marble, dove, or slate are all worked from a white ground. A feather is used to put in the veins; by this method the color is thoroughly and irregularly spread over the whole ground. All the veins must run in one general direction, and specks and dots must be added in brighter tints, with shells and fossils in lighter greys and white.
Red Derbyshire, porphry, and Irish red are all marbled off a bright red ground. Venetian red and vermilion with a little chrome are used in varying degrees of depth. The marbling is done by first glazing over the ground a coat of crimson lake, and then breaking it up by the use of a feather and turpentine with a little black. White or grey dots and veins are added in very thin white.
Green Marbles. Egyptian green and verd antique are green marbles which are worked upon a black ground. Chrome and Prussian blue, and white make the marbling colours, varying degrees of colour being used. Fossil spots and rings are added in white, cream, &c., while the innermost ground shows spaces of black. Lapis Lazuli. Lapis lazuli is used for special little medallions, &c. It is obtained from a pale blue ground ; ultramarine and gold leaf are used for the marbling and veining respectively. The veins are very fine and broken.
Graniting. Red and grey granite may be imitated by spotting a ground of either colour with white, red, grey, and black The dotting may be done with a graniting brush. Devonshire Marble. Devonshire marble is a conglomerate mass of ochres, reds, and browns, with white markings. It is represented upon a terra cotta ground by the use of feathers, sponge, and rags ; the veins being put in with a veining fitch (Fig. 72) or pencil. Alabaster. Alabaster is a favourite marble for church decoration. It may be wrought upon a creamy white ground in light red, and white and lake. It is a soft stone with undulating veins, and is readily imitated.
St. Anne’s and other black and white marbles are worked upon black grounds with white markings. Grey is also used for the middle tints. In the imitation of all marbles great attention must be paid to the shape of the masses, and the direction of the veins. The character and distinctiveness of all marbles rest principally on the form that these take, and not on their scale or size. Colour is also important, although every class of marble will present samples widely different in colour, as well as in scale. Many of the most mysterious and beautiful effects seen in marbles may be imitated by the use of turpentine, which, when sprinkled on the wet color, opens it out in fantastically shaped forms of great beauty, and renders that translucent appearance common to the richer marbles. Amber and other very translucent substances may be imitated successfully by the methods common to marbling. Repeated varnishing and re-glazing is the means adopted to produce great depth and translucency. Many exquisite suggestions in, and revelations of color may be obtained by the examination of fragments of rough marble and mineralogical specimens under the microscope. The component colouring matters in marbles are seldom seen by the ordinary observer, who only receives a general impression of the apparent colour. This superficial color may be much more truly reproduced after studying the composition of the marbles under the microscope, when the particles of coloured matter, which go to produce the effect seen, may be utilized in obtaining the required superficial effect.