How are relief carving graphics typically rendered in the design phase?

Relief carving graphics are usually rendered in the RGB palette in 256 shades of gray from black (R:0 G:0 B:0) to white (R:255 G:255 B:255). It’s important to understand that a relief carving grayscale graphic is not intended to look like a grayscale rendition of the subject. The graphic is made up of component parts, each part being assigned a color value from black to white that is only important as to the depth of the cut. The darker the color value, the deeper the cut.

—COOLaserCraft