Presentation on theme: "Ceramic Analysis. Pottery in Ancient Times Coil (vessel built from clay or with long coils by hand). Mold (vessel built from lump of clay that is pressed."— Presentation transcript:
Pottery in Ancient Times Coil (vessel built from clay or with long coils by hand). Mold (vessel built from lump of clay that is pressed into a concave mold or over a convex mold). Wheel (potter’s wheel invented in Mesopotamia ca. 5,000 B.P.-clay rotated on platform and formed with hands).
Clay Preparation CLAYS can be found near the ocean or by inland streams and ponds. The clay formed when tiny bits of dirt carried by streams sank and settled in still water ponds. Clays must be plastic enough to be rolled into a coil and bent without breaking.
Adding Temper TEMPER may be crushed shell, sand, broken pottery bits, or plant material. Up to 1/10 of the clay mixture can be made up of temper for very fine natural clays. Tempering pottery makes it able to take rapid changes in temperature when placed in a fire.
Wedge Clay WEDGE clay to make the mix even and to help remove air bubbles from the clay. If air is not removed from the clay pottery may break or crack when dried and fired.
Spiral Wedge SPIRAL type of wedging clay is an efficient way to mix clay. Keeping the clay in a cone or shell shape, first pull a melon-sized piece of clay toward you. Second, push down and away from you while giving the cone of clay a slight turn.
Pinching Pinch thumbs into the center of a ball of clay. Squeeze on the Inside with your fingers on the outside of the pot. Continue squeezing and rotating the pot until the walls of the vessel are about 1/4 in. thick. 2. Place the base in a hollow in the ground, or in a bowl shaped vessel which can be rotated easily by the potter as the pot is built up.
Coiling The coils ore rolled between the palms of the hands or rolled against a flat surface in a back and forth and center to ends direction. Coils range from 1/2 to 1 inch in thickness. To be joined properly, the coils should be roughened using a moistened stiff brush. This helps seal out any air when the calls are squeezed 10gether, and helps keep the coil moist while it is being added to the pot.
Decoration Shell edge or back of shell can be stamped and/or dragged in the clay. Cord Wrapped Paddle: used to compress the coils, leaving parallel impressions of cordage. Pointed Stick: used to make incised lines or dots on a pot. Net and Textiles: a layer keeps dirt away from the surface of a pot & leaves its mark.
Firing Native Americans of New England fired their pottery outdoors. After drying slowly for several days, pottery is ready to be baked in a fire. On a windless day, a shallow pit is dug (1) a preparation fire is built to warm the pots next to and to preheat the rocks (2) which the pottery will rest on during their firing. (3) After the first fire has burned to ashes, the warmed pots are placed upside down without their sides touching. (4) Thickly split hardwood is placed in a teepee style over the pots. (5) Quicker burning thin kindling is put under the pots and over the sides of the thicker wood. The temperature of the fire can reach 1500 degrees or more. Allow this to cool for an hour before removing pots.
Four of the pots after firing -- the black marks on the pots are not soot, they do not wash off... the marks are from the differences in oxidation and reduction of the clay; where the pot is orange, it was more open to the air (oxidized); where the pot is black, the air was cut off (reduced). Firing Results