THE ROSETTE Bill Nesse December 2006 (Originally published in the December 2006 issue of Guitar Sessions, Sessions, the on-line magazine from Mel Bay Publications. It is no longer longe r available.) Decoration on classical guitars is fairly tightly constrained by convention and the demands of acoustics. In most cases, decoration consists consists of a rosette around the soundhole and purfling at the periphery of the top and back. The headstock and the tieblock on the bridge also may be decorated. Of the decorative elements on a classical guitar, guitar, the rosette typically typically receives the most attention. While rosettes of standard design are available from commercial vendors or can be manufactured by specialty shops in Europe an d Asia, I prefer the artistic freedom and challenge of creating my own rosettes. In addition to satisfying some of my creative creative urges, this assures that the guitars that I build are uniquely mine. What is now the traditional form for classical guitar rosettes developed in the second h alf of the 19th century. The distinctive character character of those rosettes was the use of mosaic elements. Mosaics had been used before, but their use by Antonio de Torres (who established the basic geometry of the modern classical guitar) and his contemporaries set the style that has been followed for more than a century. The fact that they made some strikingly beautiful rosettes certainly didn’t hurt their acceptance. Rosette Design Traditional rosettes generally contain three types of design elements. The central mosaic carries a repeating pattern around around the soundhole. Bordering the central central mosaic on both sides are fields consisting of rings of various various colors. At the inner and outer edges of the rosettes rosettes are narrow decorative bands of a mosaic, herringbone, or braid pattern bordered by additional rings of color. The width of the rosette can vary depending on the desires of the maker, but is typically in the range of 18 to 22 mm wide. While the rosette is certainly decorative, it also has a practical function. The rosette, with its numerous rings of wood, will tend to prevent cracks from developing at the soundhole, or if they do develop, will inhibit their propagation into the rest of the top. Ideas for the design of the rosette can be found in mosaic work in ancient Roman, Greek, and Arab architecture and in a wide variety of textiles. The work of other luthiers provides additional inspiration. I particularly particularly like the the work of Manuel Ramirez, Manuel Velasquez, Francisco Simplicio, and Ignacio Fleta.
Materials The raw materials used for the rosette are different colored woods of various colors. While it is possible to dye wood to get desired colors, I prefer to use only the palette of colors found in natural wood. All of the wood for the rosette must be carefully prepared to precise thicknesses. Thin slices of wood can be cut with a bandsaw (left) and then thinned with a scraping tool, known as a filière à filets, made from a sharp plane blade (right). Veneer also is thinned to the required thickness with the same tool. Similar tools have been used by luthiers and other artisans for centuries.
Preparing the Central Mosaic The sequence of making the central mosaic is shown to the right. The central mosaic is first laid out on graph paper (a) and is designed so that it forms a repeating pattern. In this case, the repeating unit (heavy lines) is 10 columns wide and 10 rows high. This pattern is broken into its constituent columns (b) and each column of 10 small strips of wood is made up separately (see below). The columns are then glued together to form a mosaic loaf (c) from which tiles (d ) are cut so that they can be fit together side-to-side (e) to form the central mosaic.
Each of the columns in the rosette design starts with strips of thin wood (left photo) about 10-15 mm wide (a) that are glued together in the correct order (b) to form slabs. A thin slice (c) is cut from the edge of the slab on a bandsaw. Right Photo: The thin slice is carefully thinned with the scraper so that the individual pieces of wood have a square cross section. This process is repeated for each of the columns in the design.
The ten different columns that comprise the mosaic design have been glued together to form the mosaic loaf. In this design, each of the individual pieces of wood has a cross section of 0.5 x 0.5 mm. Individual tiles are then cut from the loaf to be used in making the rosette.
Decorative Bands The diagonal or braid pattern that forms the inner and outer decorative bands is made from additional pieces of veneer. These are glued together in a repeating sequence (a). A thin slice is cut on the diagonal from the edge (b). A backing strip of veneer is glued to one side (c) to provide stability and becomes part of the rosette design. This braid also may be used as part of the purfling around the edge of the top and on the bridge’s tie block so that the decorations form a coherent whole.
Completing Preparation Additional strips of veneer are prepared to make up the various rings in the design and a trial section of rosette is assembled to allow the design to be evaluated. The rosette is installed in three steps, the inner rings first, then the mosaic tiles, and finally the outer rings. The veneer strips and associated sections of braid pattern are organized into these groups. The soundboard, which makes the background for this photo, is prepared for the rosette by sanding both sides smooth and drilling a hole in the center of the soundhole location. The hole is mounted on a bushing protruding from a work board.
The rosette must be let into a 2 mm deep recess cut into the soundboard. To cut the boundaries of the channel I use the circle cutter shown to the right. It consists of a sharp blade mounted in an arm that can be moved in or out to change the radius of the cut. It pivots on the bushing at the center of where the rosette will be installed. This is another tool that would be at home in a 17th century shop. .
Inlaying the Rosette I The channel for the inner rings of the rosette is prepared by cutting the outlines with the circle cutter (left ) and then using a sharp chisel to remove the waste in between (right ). The rosette does not make a complete circle. The missing section will be beneath the fingerboard and therefore hidden when the guitar is completed.
The pieces that make up the inner rings of the rosette are organized in the proper order and then glued into the channel.
Inlaying the Rosette II After the first section of the rosette has dried, it is planed down to near the surface of the soundboard and then the channel for the mosaic tiles is cut. Tiles are cut from the mosaic loaf and are then glued in place between bordering rings of wood.
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Inlaying the Rosette III The channel for the outer section of the rosette is cut next and those pieces are glued in place.
. The Finished Rosette The finished rosette has been sanded down flush with the soundboard. The sound hole will not be cut out until after the top has been cut to shape and worked down to the final thickness.
. I like my rosettes to have a clean, uncluttered look. For the rosette illustrated here, the mosaic utilizes a white field with a pattern executed in two different dark woods that I expect will age differently to yield some interesting subtleties in future years. Bordering the mosaic are rings of a dark red wood that tend to pull the eye to the mosaic and define that design element. To provide coherence to the design, woods used in the central mosaic also are used elsewhere. A braid pattern is used for the inner and outer decorative elements. This braid and its bordering strips are made from three different woods. The braids converge to the center of the rosette to give it a sense of movement and to lead the eye in to the mosaic. The rings of the field are made from lighter colored woods and are intentionally fairly bland to avoid too much going on in the design.
The rosette shown here uses three different woods to produce a sinuous curve on a white field with small accents in the convex parts of the curve. A herringbone pattern forms the outer decorative bands that are arranged to produce a counterclockwise sense of movement.
My current practice is to create a different rosette for each guitar I build. While inlaying the rosette into the top is one of the first steps in building a guitar, it establishes the pattern for decoration on the instrument as construction progresses. Inlaying the rosette also gives me a very tactile and direct sense of the top wood's properties. This helps me to get a better sense for the sound that the top wood is capable of providing, and guides me in the critical task of graduating the top thickness to achieve the sonority that I want the guitar to have.
