What is terra sigillata and why is it important?
Terra sigillata is an ultrarefined clay slip that can give a soft sheen when applied to bone-dry wares and, if polished or burnished while still damp, may give a high gloss. The ancient Greeks and Romans used this technique in lieu of glaze.
What is terra sigillata glaze?
Terra sigillata is a very smooth, lustrous coating of clay which resembles a glaze and is virtually waterproof. The name means “sealed earth” and has been used to refer to the Classical Greek Attic black-figure and red-figure painted pottery.
How do you make a terra sigillata?
Making terra sigillata involves mixing water and a suitable raw clay powder with a small quantity of deflocculant. This is left to settle, and the deflocculant helps separate fine and coarse clay particles. Once settled, the top layer is siphoned off and condensed down through evaporation to create terra sigillata.
Did the Romans use Terracotta?
Fired clay or terracotta was also widely employed in the Roman period for architectural purposes, as structural bricks and tiles, and occasionally as architectural decoration, and for the manufacture of small statuettes and lamps.
How did the Romans make terra sigillata?
The body of the ware was generally cast in a mold. Relief designs, taken from a wide repertory of patterns and figurative scenes, were also cast in molds (which had been impressed with stamps in the desired pattern) and then applied to the vessels.
What are mason stains?
Mason Stains are powdered pigments made of a combination of oxides and frits that create beautiful uniform rich colors. You can add mason stains to dry glaze recipes to produce color in an opaque or transparent base glaze. Mason stains can be mixed with water to create washes that add a splash of color.
What is a Deflocculant?
Definition of deflocculant : an agent that causes deflocculation specifically : a chemical (as sodium carbonate) added to a clay slip to minimize settling out.
What is the specific gravity of terra sigillata?
1.10 to 1.20
The workable specific gravity range for terra sigillata is 1.10 to 1.20, with 1.15 being ideal for application and colored terra-sigillata mixing. At the low end of specific gravity (1.10) you will need to apply multiple layers to create an opaque coating.
Can you sgraffito on bone dry clay?
Sgraffito usually involves carving up a bit of the underlying clay as well as the decorative underglaze or slip. So, a common question is whether you can do sgraffito on bisque clay. Well, the answer is yes, you can.
What Colour were Roman pots?
A glossy brick-red tableware which was primarily used for displaying and serving food. This was usually their best plates and bowls.
What is terra sigillata?
The purity of terra sigillata is perhaps most celebrated on fine Roman Arretine wares, with the monochromatic red high-gloss coating emphasizing complex relief decoration. But like so many innovations of the Romans, the technology was completely lost in the early medieval era.
How do you reduce terra sigillata?
Other Ways to Reduce Terra Sigillata: 1 Putting your mixture in a pan and simmering it on low heat for a few hours. 2 Leaving the mixture in a shallow dish or container without a lid on for a few weeks. At room temperature, the water… More
What is a terra sigillata refined slip coating?
Traditionally, the primary objective of terra sigillata refined slip coatings is to get a high satin gloss without a glaze, using simple, time-effective polishing methods. Most of the popular published terra sigillata recipes do not separate the large particles adequately, and the product is not a true terra sig.
How much clay do I need to make terra sigillata?
After settling, siphoning, and concentrating, that will yield about a half gallon of super-refined terra sigillata. A near-full five-gallon bucket of initial mixture will take about 14 lbs. of Redart, Goldart, kaolin, fire clay, or any dry claybody, or about 11 lbs. of ball clay.