Modern rosettes basically have three basic areas: an inner ring that surrounds the sound hole, a central decorative mosaic, and an outer ring that usually contrasts with the inner ring. Additional simple line purlins separate these areas. Peripheral rings are usually made of single slat, herringbone or checkerboard laid diagonally.
The central mosaic is the most challenging part of rose design and implementation. The first is the mosaic design itself, which is usually done on photo paper. These squares are filled to create the curves, angles, and colors of the roughly square "tiles" of the rosette. This will be the basic repeating element of the mosaic, and it can be confusingly simple or incredibly complex.
Appropriately colored veneer wood chips are scraped to a regular thickness of about 0.5 mm. These veneers are then stacked to correspond to each vertical square column in the design grid, and then glued and clamped. In the same direction as the appropriate vertical design column, the slender sheet is cut into 0.5mm thick wooden boards, and its end view will match each corresponding vertical design column. In graphic design, each subsequent vertical column will have a different plank.
Next, glue the wood boards that match each vertical design post together to make a "log" (or "bread"). The end texture of the assembled log should now match the blueprint design. Because the rosette ends up round, the side closest to the sound hole needs to be slightly narrower than the outside, like a slice of pizza. Some luthiers shave the burr to get this taper, others apply more clamping pressure to the edge when gluing to compress it.
The final log is cut into a texture parallel to the end (think of slices of bread) to get individual tiles that will be inlaid with a mosaic design.
Some luthiers used a fixture and built the entire layered rosette before inserting it into the groove on the top of the guitar. Others build them to the top layer by layer. Once the glue is dry, the inlay is scraped flat with the guitar panel, like a classical guitar rose!
Edit by Height Musical Instrument News Department