The color variations in some of Collings' rosettes which can appear to be a defect is part of the character of all Collings guitars with a standard rosette. The center band of concentric circles is a ribbon of “celluloid tortoise”, the same material used for bindings, pick-guards, and some purfling. This celluloid material is supplied to the builders in the form of a sheet, from which they can cut narrow strips for purfling & inlays, as well as to craft their own pick-guards. Imagine a tortoise pick-guard, with multi-colored opaque areas scattered throughout the pattern... In the case of purfling material, narrow strips of multi-colored celluloid are stacked & glued, then inlaid on their side with the edge facing outward.
The opaque areas in the rosette are where the pattern is lighter in color, and occurs naturally in all tortoise materials. If you examine photos of any of our Collings, you will see this is uniquely patterned on each rosette that features this strip of tortoise material. Like grain striations in wood patterns, we have come to appreciate the color variance in tortoise to be part of the unique character of each guitar. When using this same material for the body binding (which is much wider), you will notice that many builders utilize a B/W/B purfle line (otherwise known as 3 small strips of celluloid, black then white then black), which prevents light from shining through the opaque areas in the tortoise, or otherwise emphasizing this phenomenon.
