  Chapter XII referred to clay as a free and plastic material adapted to a wide range of surface enrichment processes. Metal as a more refractory material offers greater resistance to the craftsman and is relatively more limited in its capacity for surface enrichment. As was the case in the consideration of contour enrichment for designing purposes, it is necessary in the consideration of surface enrichment to divide metal into two groups: precious and base metals. As the field of design in both base and precious metals is large, we shall consider the surface enrichment of precious metals only in this chapter. Divisions for Enrichment Following an order similar in character to that used in clay designing, problems in both base and precious metals may be divided into four classified groups as follows: flat, square, rectangular, or irregular planes; shallow circular forms; low cylindrical forms; high cylindrical forms. Designs included in the first group, flat planes, comprise such problems as are typically represented by tie pins, fobs, rings, and pendants. The design problems presented by these examples are so important that it is wise to restrict this chapter to flat planes. Rule 10g. The inceptive axis should pass through and coincide with one axis of a stone, and at the same time be sympathetically related to the structure. Rule 10h. The position of the inceptive axis should be determined by: (1) use of the project as ring, pendant, or bar pin, (2) character of the primary mass as either vertical or horizontal in proportion. Inceptive Axes and Points of Concentration The semi-precious or precious stone is commonly found to be the point of concentration of these designs. The inceptive axes of tie pins, pendants, and fobs are generally vertical center lines because of the vertical positions of the objects when worn. The inceptive axes, The point of concentration for tie pins, pendants, and fobs in formal balance, in addition to coinciding with the inceptive axis, is generally located above or below the geometric center of the primary mass. The point of concentration for rings and bar pins is placed in the horizontal inceptive axis and centrally located from left to right. Typical Processes of Enrichment Economy of Material As a step preliminary to designing, and in order that the enrichment may be conventionalized or adapted to conform to the requirements of tools, processes, and materials, it is now imperative to become familiar with a number of common forms of surface enrichment in metal. There are eight processes frequently encountered in the decoration of silver and gold: piercing, etching, chasing or repoussÉing, enameling, inlaying, stone setting, building, carving. To these may be added planishing, frosting or matting, and oxidizing as methods employed to enrich the entire surface. Economy of material is of prime importance in the designing of precious metal and, particularly in gold projects, conservation of the metals should be an urgent consideration in all designs. Rule 10a. Designs in precious metals should call for the minimum amount of metal necessary to express the idea of the designer for two reasons: (1) good taste; (2) economy of material. Evolution and Technical Rendering of Processes A non-technical and brief description of each process follows. All designs in this chapter may be identified by referring to the process numbers after the figure description as 1, 3, 5; 2, 4, 6, corresponding to the key numbers on Plate 52. A design to be submitted to the craftsman should be a graphic record of technical facts in addition to good design, which requires that we should have an expressive technical means of rendering each process. The last column, on Plate 52, indicates this rendering. In addition to this rendering each one of the eight technical processes has been carried through three design steps. 1. (first column, Plate 52) Planning the original primary mass, with its inceptive axis suggested by the structure and intended use. It passes through the point of concentration. 2. (second column, Plate 52). The division of the primary mass into zones of service and enrichment with the suggestion of the leading lines which, at some points, are parallel to the contours and lead up to the point of concentration. The contours in this column have, in several instances, been changed to add lightness and variety to the problem. 3. The last step (column three, Plate 52) shows the design with graphic rendering suggestive of the completed process. Plate 52 Piercing 1. Removal of design unit or background by means of the jeweler's saw. Bridges of metal should be left to support firmly all portions of the design. Test this by careful study of the design. Rendering—shade all pierced portions of the design in solid black. Slightly tint portions of the design passing under other parts. Illustration, Figure 336. Rule 10j. All surface enrichment should have an appearance of compactness or unity. Pierced spots or areas should be so used as to avoid the appearance of having been scattered on the surface without thought to their coherence. Etching 2. Coating either design or background with an acid resistant, to be followed by immersion of the article in an acid bath. Allow the unprotected portion to be attacked and eaten by the acid to a slight depth. Rendering—slightly tint all depressed or etched parts of the design. Illustration, Figure 339. Chasing or RepoussÉing 3. The embossing and fine embellishment of a metal surface by the application of the hammer and punches. The work is conducted mainly from the top surface. Rendering—stipple all parts of the background not raised by the process. Chasing should seem an integral part of the background and not appear stuck upon it. Illustration, Figure 342. Rule 10k. Enameling (Champleve) 4. A process of enameling over metal in which the ground is cut away into a series of shallow troughs into which the enamel is melted. Exercise reserve in the use of enamel. Over-decoration tends to cheapen this valuable form of decoration. Rendering—shade the lower and right-hand sides of all enameled areas to suggest relief. Illustration, Figure 345. If possible render in tempera color. Plate 53 Rule 10i. Caution should be exercised with regard to the use of enamel. Over-decoration by this material tends to cheapen both process and design. Rule 10l. The lanes or margins between enameled spots should be narrower than the lane or margin between the enamel and the contour of the primary mass. Inlaying 5. The process of applying wire, etc., to an incision on metal either by burnishing or fusing the metal into the cavities. Rendering—tint the darker metal or, if possible, render in color. Illustration, Figure 348. Stone Cutting 6. An enrichment of the surface by the addition of semi-precious or precious stones. Other enrichment is generally subordinated to the stone which then becomes the point of concentration. All enrichment should lead toward the stone. Small stones may, however, be used to accentuate other points of concentration in surface enrichment. Rendering—shade the lower and right-side of the stone to suggest relief. Pierced subordinate enrichment should be shaded in solid black. A concentric line should be drawn outside of the contour of the stone to designate the thin holding band, or bezel, enclosing the stone on all sides. Illustration, Figure 351. Rule 10d. Surface enrichment should at some point parallel the contours of both primary mass and point of concentration, especially whenever the latter is a stone or enamel. Rule 10e. In the presence of either stone or enamel as a point of concentration, surface enrichment should be regarded as an unobtrusive setting, or background. Rule 10f. Stone or enamel used as a point of concentration should form contrast with the metal, either in color, brilliancy, or value, or all three combined. Building 7. The process of applying leaves, wire, grains, and other forms of surface enrichment to the plane of the metal. These may afterwards be carved or chased. Rendering—shade the lower and right-hand lines; slightly tint the lower planes of the metal. Illustration, Figure 354. Courtesy of the Elverhoj Colony Figure 372a.—Tie Pins Courtesy of the Elverhoj Colony Figure 372b.—Tie Pins Carving 8. The process of depressing or raising certain portions of the metal surface by means of chisels and gravers. By the use of these tools the surface is modeled into planes of light and shade, to which interest is added if the unaggressive tool marks are permitted to remain Rule 10k. Built, carved, and chased enrichment should have the higher planes near the point of concentration. It is well to have the stone as the highest point above the primary mass. When using this form of enrichment, the stone should never appear to rise abruptly from the primary mass, but should be approached by a series of rising planes. Planishing 9. The process of smoothing and, at the same time, hardening the surface of the metal with a steel planishing hammer. The hammer strokes give an interesting texture to the surface which may be varied, from the heavily indented to the smooth surface, at the will of the craftsman. The more obvious hammer strokes are not to be desired as they bring a tool process into too much prominence for good taste. Rendering—print desired finish on the drawing. Frosting 10. A process of sand blasting or scratch brushing a metal surface to produce an opaque or "satin" finish. Rendering—similar to planishing. Oxidizing 11. A process of darkening the surface of metal by the application of chemicals. Potassium sulphite will supply a deep, rich black to silver and copper. Rendering—see Planishing. Design of Pins and Brooches The eleven processes mentioned above are among those which, by recent common practice, have become familiar to the craftsman in precious metals. While they do not cover the entire field, they at least give the beginner an opportunity to design intelligently in terms of the material. Dependent Surface Enrichment for Pins Plate 53 is mainly the enrichment of the flat plane by the addition of semi-precious stones (process six). Whatever surface enrichment is added to this design becomes dependent enrichment and quite analogous to dependent contour enrichment, Plate 29, inasmuch as it has to be designed with special reference to the shape and character of the stone. Figures 358 to 363 are examples of dependent contour enrichment; Figures 364 to 371 are examples of dependent surface enrichment. Figures 358 to 367 are based upon vertical inceptive axes as appropriate to their intended service. The point of concentration may be located at practically any point on this inceptive axis, provided the major axis of the stone coincides with the inceptive axis. The best results are obtained by placing the stone a little above or below the exact geometrical center of the primary mass. Plate 54 Inceptive Axes for Pins Figures 368 to 372 show articles based upon a horizontal inceptive axis. The stone, in accordance with formal balance, is in the geometric center from left to right. One notices the important fact that the surface enrichment must bring the stone and contour together in sympathetic relation and, at the same time, be related to both stone and contour. This again brings out the meaning of dependent surface enrichment. The contour enrichment is to be kept as simple as possible and the interest concentrated upon the surface enrichment. The accentuation of both surface and contour enrichment in a single design marks the height of bad taste in design. Rule 10b. Contour and surface enrichment should never appear to compete for attention in the same design. Fobs Plate 54 shows flat planes, the service of which suggests vertical inceptive axes. Figure 380 is noted as an exception to this vertical inceptive axis as it possesses a vertical primary mass but with radial inceptive axes. The interesting manner by which the dynamic leaves of the outer border transmit their movement to the inner border, which in turn leads toward the point of concentration, is worthy of attention. The points of concentration in other designs on this plate are all contained in the vertical inceptive axes. Rings Plate 55, at first thought, would seem to fall under the classification of low cylindrical forms but when reference is made to Figure 385 it is readily seen that the ring has to be first developed as a flat plane, to be afterwards bent into the required form. Care should be taken to keep the design narrow enough to be visible when the ring is in position on the finger. Plate 55 The long horizontal band of the ring supplies the motive for the horizontal inceptive axis as a common basis or starting point for a large number of designs. If the designer so desires, the vertical axis of the finger is authority for an elliptical stone to be placed with its major axis as a vertical line in harmony with the finger axis. In any instance the designer seeks to lead the eye from the horizontal portion of the ring (the finger band) toward the point of concentration (the stone), by means of surface enrichment. A long sloping Courtesy of the Elverhoj Colony Figure 390a.—Rings Plate 56 suggests some vertical flat planes for pendants. While no definite rule can be stated for the location of the stone, from past experience, it is easier for beginners to place the stone on the vertical inceptive axis slightly above the geometric center of the primary mass. Figures 391 to 395. A design thus formed is less likely to appear heavy, although there is nothing arbitrary about the suggestion. Rule 10c. Parts of a design differing in function should differ in appearance but be co-ordinated with the entire design. Plate 56 Pendants and Chains In pendant design the surface enrichment generally carries the attention from the contour of the pendant to the stone, thus insuring Rule 10m. Transparent and opaque stones or enamel should not be used in the same design. Relation of Stones to Metal For the designer's purposes we may consider two kinds of stones, the transparent and the opaque. These should not be mixed in one design. The most favorable stones are those forming contrasts of value or brilliancy with the metal as, for example, the amethyst, lapis lazuli, or New Zealand jade, with silver; or the dark topaz, or New Zealand jade, with gold. Lack of these contrasts gives dull, monotonous effects that fail to make the stone the point of concentration. Figure 467. These effects may be partially overcome by frosting, plating, or oxidizing the metal, thus forming stronger contrasts of value.
Courtesy of the Elverhoj Colony Figure 401a.—Pendants Courtesy of the Elverhoj Colony Figure 402.—Pendants
Rules 10a to m: Surface Enrichment of Small Flat Planes of Precious Metal. IA=Inceptive Axis. Instruction Sheet Plate 57
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