Once the plaster has set, you can choose to leave your casting with the same
natural finish it acquired from your face. This can produce striking shadows and dramatic effects. Use a strong light from a shallow angle to produce stark shadows and highlight edges and texture. Light from a more natural angle, or diffuse light give fewer shadows and a more realistic look.
Natural-finish pieces tend not to look a lot like the model to a human eye. Unarguably, the features and details are exactly identical, but when the human visual system loses all cues of color and translucency, the other-ness reduces our ability to recognize the face, and leaves us staring at the art. This effect can be reduced by smoothing out the finer details of skin texture. The picture on the left is just as it left the mold. On the right, a cast from the same mold has been sanded smooth.
A more classic look is also available. Atomized bronze embedded in a polymer/plaster matrix gives this casting not just the look of metal, but the ability to withstand weather and patina like solid bronze, at a fraction of the cost of foundry work. Castings made in this fashion are 75% bronze by weight.
The identical process gives a very different look with coarser bronze particles. This cast has been sanded smooth, and then buffed to reveal the metal above the plaster matrix. After buffing, the entire piece was burnished to flatten and spread the surface particles. The piece has been well-photographed here, but the final look of this finish is not quite identical to solid bronze; some residual whiteness of the plaster matrix is still visible in strong light.
Coarse bronze is an ideal choice for outdoor applications. The cost is less than that of the fine bronze, and will acquire a patina just as well.
This piece is another example of bonded coarse bronze. This piece has not been burnished, and so does not have the mirror-like shine. It has a bit of natural patina beginning to form, which shows here as a slight green cast, especially in the creases of the eyes.
Surface colors can also be applied to the plaster, whether smoothed or not. Brushed pa
ints and spray paints do well on plaster, and help to fill in pores and small wrinkles. The possibilities for color are unlimited. If you want a metallic finish, but are put off by the cost of the actual bronze, there are some surface treatments shown here that will give the look of copper, aluminium, gold, brass, or bronze. Please be aware that these finishes are not suitable for outdoor installation.
The six finishes below are all paste wax. They contain very fine metal powder plus pigment in a wax base. They polish to a nice luster, and will reflect glancing light quite well.