Materials and Processes

MODELING

Relief sculpture can be created in many different materials and processes. The most basic is to work in soft clay, which is an additive process, whereby the form is modeled into shape. Additive processes are any that allow for easy buildup of material, including ceramic clay, oil-clay, and wax. Additive processes are the most forgiving, as the material can also easily be taken away. Modeling is done when the material is pushed and pulled into shape.

Winged Porcine Beast from the early Tang dynasty or Northern Qi, reddish earthenware relief with appliqué and amber and green glazes,

h. 34.7cm, w. 33.2 cm, approx. d. 4.0 cm.

CARVING

A more demanding undertaking is carving, which is a subtractive process. Hard and unforgiving materials are appropriate for carving, such as stone and wood. There is little room for error in a carving, so many artists first make a prototype in clay. The nature of materials for carving generally make adding back very difficult or even aesthetically unacceptable.

Some materials are transitional, such as plaster, which can be cast into a block for carving, or can be modeled while wet. Even water-based clay can be transitional, whereby it is modeled until it becomes dry, at which point it can be carved before firing.

       

Left: Pigment Box in Half Moon Shape, carved wood, 6.75 x 32.1 x 16.4 cm, from Zaire, Kuba. Right: Fragment of engraved jadeite tablet, unfinished reconstruction, 13.7 cm x 11.1 cm x 0.7 cm, from Sacred Cenote at Chichen Itza in Yucatan, Mexico

 

CASTING

Any relief that was either modeled or carved could later be molded and cast to solidify or reproduce the work. Take, for example, the relief sculpture below. It is a cast replica of a relief from Angkor Wat of the Demon Ravana on his Chariot from first half of the 12th century. This 203 x 64 cm detail is cast in plaster from a silopren mold (silopren is a type of silicone rubber). Note how faithfully it replicated the finer details of the original carved stone

Three-Figure Plaque from the Benin Kingdom, Nigeria. c. 1500-1700. Cast bronze.

 

 

FORMING

Another material for use in relief sculpture is malleable sheet metal. The most economical metal is aluminum, which is readily available. Copper, silver, brass, nickel, and gold are also common, with unique aesthetics, properties and cost. All have the ability to be made to their own level of dead-soft. This is the process of heating the metal to annealing temperature, whereby the internal stresses in the metal are eliminated, and as it cools, recrystallizes to its softest level. As the metal is worked, new stresses are introduced, causing it to become work hardened, and eventually brittle. However, re-annealing brings it back to dead-soft.

• Engraving- Metal Forming relies on techniques of hammering and shaping. However, there is also a process of carving metals, called “Engraving”, whereby a fine chisel is employed to carve away the metal surface.
• Repoussé* - to hammer into relief from the back side of a metal sheet, causing these areas to rise above its face on the front side.
• Chasing* - to hammer into relief from the front side, causing the metal to sink below its face on the front side.
• Embossing**- Stamping metal into raised relief using a die. This can also be done by rubbing the soft metal into the die from the back side with a smooth tool. A larger tool is used for broad areas, and a finer pointed tool is used to refine the edges and details.  Machine embossing is a fast production method of creating relief in metal.
• Debossing**- Stamping metal into depression on the metal surface. This is the reverse of embossing.

* Note, Repoussé and Chasing are done against a malleable material, such as a pitch pot.

** Note, Embossing and Debossing are also a wonderful techniques for use with paper

 

 

Left, a Repoussé copper beetle by metalsmith Fred Zweig, illustrating the extreme malleability of copper. This is a lossless process, and depicts a high relief. Right, Gold-copper alloy Earspool with Spondylus Shell Diving Scene by an unknown Chimú artist, c. 1000 - 1450 CE, showing a low relief effect.

CITATIONS

Africa, Nigeria, Benin Kingdom. Three-Figure Plaque. c. 1500-1700. Artstor, library.artstor.org/asset/AMICO_CL_103802986

Chinese. Winged porcine beast. 6th-7th century. Artstor, library.artstor.org/asset/APRINCETONIG_10313684900

Demon Ravana on his Chariot. Detail of a relief at Angkor Wat (north gallery/west wing) [Dämon Ravana auf Kampfwagen; Detail von einem Relief in Angkor Vat (Nordgalerie/Westflügel)]. cast replica of relief from first half of the 12th century. Artstor, library.artstor.org/asset/BERLIN_DB_10313750905

Earspool with Spondylus Shell Diving Scene. 1000 - 1450 AD. Artstor, library.artstor.org/asset/SS35538_35538_29885674

Fragment of engraved jadeite tablet, unfinished reconstruction (TP/68). Artstor, library.artstor.org/asset/AHARVARDIG_10313276014

Zaire, Kuba, African; Central African; Congolese; Kuba, African; Central African; Congolese. Pigment Box in Half Moon Shape. 19th-20th Century. Artstor, library.artstor.org/asset/AMICO_DALLAS_103842267