What process is described as best when only one reproduction of a sculpture is needed?

The process described as best when only one reproduction of a sculpture is needed is waste molding. Waste molding is particularly effective for creating a single piece from an original sculpture because it involves creating a flexible mold around the original form and then producing a one-off reproduction, typically made from materials like plaster or resin. This method allows for the capture of fine details and unique textures of the original sculpture.

In contrast, shell molding and bronze casting are more suited for producing multiple copies. Shell molding typically involves creating a rigid shell mold that can be reused, making it advantageous for mass production. Bronze casting requires a more complex setup and is generally used to create durable, multiple copies due to its ability to withstand wear and environmental conditions, making it less ideal for a singular reproduction. Plaster casting can be used for individual pieces, but it typically requires a more labor-intensive process involving creating a second mold from a first one, which may not be as efficient as waste molding when only one reproduction is desired. Thus, waste molding stands out as the optimal choice for producing a single sculpture reproduction.