Page:Encyclopædia Britannica, Ninth Edition, v. 4.djvu/570

Rh 508 be well rubbed with pumice stone, to take off the old paint as much as possible before the new work is proceeded with. Incised For a decoration to rooms having plastered walls, plastering, instead of papering or flat painting, or for a suitable orna mentation for the interior of churches built at small outlay, the old system of pargetting has been revived. The usual stucco or other plaster finish is, while still wet, stamped over with a pattern made of brass, or for rougher work of wood, to any geometrical or other form in accord ance with the style of architecture ; this indents the sur face. It may be left all of one colour, or the open por tions of the device may be filled in with another coloured plaster. Another revived method, especially for outside work, now Sgraffito, much in use is called sgraffito. It was in vogue with the Italian artists about two centuries since, who executed some very elaborate specimens of ornamentation with it. The process is briefly as follows : First, mix with the mortar some colouring substance of the tint desired for the pattern of the design ; then apply a thin coat of it to the wall. When this coat is nearly dry, apply on it another coat similarly prepared but of the colour intended for the grounding, and then, a mould having been prepared in zinc of the exact outline of the pattern, it is to be applied to the surface, its outer edge marked round, and with a sharp tool as much of the upper coat of plaster is cut away as comes within the pattern, down to the face of the lower coat. By a careful arrangement of pattern, a consider able variety of colouring may be employed ; and even three coloured coats can be put on, cutting through some times one, sometimes two, as may be desired to represent the design. As the colour is in the material itself, there is no fear of its scaling and so presenting a bad appear ance ; and it is a comparatively cheap process for the decoration of a new surface which cannot be painted for some time. The process has been adopted in England with coloured cements for outside work. Under the plasterer s trade it may be desirable to men tion some of the varieties of artificial marbles, scagliola, and other similar work for the decoration of buildings. Scagliola. Scagliola is a species of plaster or stucco invented about 1000-50 in Italy. The work is lathed and plastered as usual, and then the artist commences, preparing his material, which is composed of the purest gypsum broken into small pieces and calcined, passed through a very fine sieve and mixed up with glue, isinglass, ttc. In this solution the colours are diffused that are required to be imitated in the marble ; or the colours are prepared separately, and after wards mingled and combined nearly in the same manner that a painter mixes the primitive colours on his palette to compose his different tints. When the gypsum is prepared and mingled, it is laid on the plaster, and then floated with proper moulds of wood, the artists during the floating using the colours necessary for the imitation, by which means they become mingled and incorporated with the surface. The process of polishing follows, first by means of pumice stone, then with tripoli and charcoal and fine and soft linen ; after this the surface is rubbed with a piece of felt dipped in a mixture of oil and tripoli, and last of all with pure oil. The imitation may be so good that except by fracture or by sound it cannot be discovered to be a counterfeit. Other Marezzo marble is made of cement mixed with fibre for imitation strength and to resist a blow. Slabs are bedded on plaster of Paris, and with cramps and dowels like marble. Every variety of marble can be imitated in it, and it receives a high and permanent polish. The Marbre Universel Company have put forward a new manufacture of a similar descrip tion. marbles. [MODELLING. MODELLING, CARVED WOIIK, AND GILDING. The modeller copies the drawings of the designs which Model] may have been prepared for the enrichments, in what ever material they are to be cast, whether in plaster, in metals, or in composition of any kind, for the plasterer, smith, or decorator. The model is made of soft wood, by the usual chisels and gouges, or in a finely-tempered arid plastic clay called modelling clay, or in wax. The modeller works the clay with his fingers, assisted by a few ivory, bone, or steel tools for finishing off neatly and sharply, and for working in parts which he cannot reach with his fingers. The best workman is one who can do most to wards producing the required forms with his fingers, unassisted by artificial tools, as a greater degree of ease and freedom almost always results from the use of the hands alone. The model being completed, it is moulded, that is, a mould or moulds are made from it of a preparation of resin or of gelatine, sometimes of plaster of Paris ; the moulds, if they have to be formed in portions, are fitted exactly to each other at the edges, and in these moulds casts in plaster of Paris or other material are made to any extent that may be required. For smith s work the wood model is sent to the founder for casting in metal. For carved work, such as caps of columns, shields, medallions, consoles, etc., the model may be sent to the mason or stone carver for the completion of the block, which may have been left in a boasted state by the mason when setting it. The modeller having some pretensions to be considered an artist rather than a mere artificer, is for the most part paid according to his merits, rather than for so much time, according to the ordinary mode of determining the value of artificers works. The carver is strictly an independent artist, whose busi- Carved ness it is to cut ornaments and enrichments in solid and work, durable material, such as stone arid wood, so that, like the modeller, he must be paid according to the taste and power he may exhibit in his works, rather than as a common artificer. The art of carving has, however, been in a great measure superseded by modelling and casting. In works of a free style, or of a mediaeval character, the carver is often left free to exercise his own taste and fancy or talents in the execution, with or without a sketch by the architect before him. The decorator, in addition to casts Decora in plaster of Paris, now makes use of composition orna- work, ments, which are formed of a mixture of whiting and glue pressed into moulds ; or of papier mache, which is paper pressed into nxmlds ; or of a composition of a thin coat of plaster of Paris poured into the mould, and then covered with coarse canvas, the result being to all appearance a plaster cast, but it is far lighter in weight, a figure the size of life being readily moved about by one person. It was an old process revived by the late Mr Owen Jones, and well carried out for him by M. Desachy, in the elaborate ornamented ceiling at St James s Hall, Piccadilly. Gilding is applied to castings as Avell as to carvings ; Gilding but the former being, almost as a matter of course, less sharp and spirited in their flexures and details, as well as less firm in substance than the latter, castings can less bear- to be further subdued by the application of foreign matters to their surfaces than carvings may. Gilding is the appli cation of gold leaf to surfaces, which require, however, to be previously prepared for its reception. The work is first primed with a solution of boiled linseed oil and carbonate of lead, and then covered with a fine glutinous composition called gold size, on which, when it is nearly dry, the gold leaf is laid in narrow slips with a fine brush, and pressed down with a piece of cotton wool held in the fingers. As the slips must be made to overlap each other slightly, to insure the complete covering of the whole surface, the loose