Opening begins the throwing process. The potter must maintain the strength of the clay, optimized by wedging and centering, during opening and throwing. Opening is the process of throwing to create the void that defines the inner volume of the form. On-center opening establishes the true base of the inside wall, creates equal wall thickness, and defines the shape of the pot. Creating and maintaining fairly equal wall thickness during opening allows fluid movement of the clay during throwing. Production and control of the high points facilitates opening and throwing.
Fold: A directed touch at the crest of a high point which pivots on a point to redirect the flow of the clay platelets from horizontal to vertical or vertical to horizontal.
High Point: Three types of high points must be identified when forming clay: extra thickness high points, change of direction high points, and hidden high points designating the beginning or end of a buttress of extra thickness.
Move Against the Spin: During opening and throwing, a move against the spin controls the horizontal high point, which is created by the pressure of your hands.
Throwing During Opening: Moving the clay displaced by opening out and up into the wall.
True Base of the Inside Wall: The point at which the weight of the wall is carried. Usually located one wall’s thickness toward the center from the base of the inside wall. When throwing during opening, the true base of the inside wall is the crest of the vortex (1).
Newton’s Third Law of Motion
For every action, there is an equal and opposite reaction. Clay moves in response to the potter’s touch, centrifugal force, and the pull of gravity. High points form due to the fluidity of the clay or a directed touch. The potter must control any unwanted high points and create desired high points to direct the clay where it’s needed.
To direct or control a high point, the angle of approach and force of our touch determine the movement of the clay. Centrifugal force, controlled by the rate of the spin of the wheel, moves clay up and out, and gravity pulls it down. Reading the clay at any moment in time allows the potter to respond and direct the movement of the clay, harness centrifugal force to assist in throwing, and oppose the pull of gravity.
Opening is impeded by displaced clay that needs to move somewhere. The most common down-and-out force of the potter’s hands results in a struggle to move the clay back in and up into the wall. Instead, by directing the movement of the clay as you open, you have control. Your inside hand moves the clay layer by layer across the floor to the outside of the wall. The outside hand roams to find the high point of displaced clay forming on the outside wall and, at the crest of the extra thickness high point (1), folds to redirect the extra thickness of clay in and up the core of the newly established wall. With each fold, the height of the wall increases. Throwing during opening establishes an upward particle alignment in the new wall, which is critical to the fluid upward movement of the clay during the subsequent throwing of the form.
As the inside hand begins the opening by moving down in the lower right-hand quadrant at the crest of the vortex, moving against the spin keeps the form on center. As clay is directed toward the center to create the floor, the floor is strengthened by dispelling any high point that forms in the center bottom. At the center, repositioning of your inside hand is required to move against the spin, throw the hidden high point, and rebound clay toward the outside wall. The outside hand finds the crest of the high point as it forms on the outside wall and pivots or folds the emerging high point of displaced clay up into the wall. Without a move against the spin, the form is knocked off center. Create the rim, create the foot statement, and the opening is complete. A skillful opening begins the throwing of the pot.
These are the skilled moves. How do we get there? The final movement of centering is down on the outside and up the core. Movement in opposition to the previous move strengthens by compressing and re-aligning particles. An opposing movement down the core and up the outside defines the opening. Clay moves to the nearest dynamic high point. If you create a high point on the outside, prior to throwing down on the inside, clay will move toward the high point. If you maintain a strong rim statement during throwing, centrifugal force moves the clay toward the rim. Controlling the outside high point rebounds the clay in and up the core of the newly established wall, and the rim grows. The throwing of the pot is almost complete.
Opening can be achieved with many different hand positions depending on the amount of clay to be opened. The key when directing the clay down and out, is that your hands must stay in the lower right-hand quadrant. Move against the spin, from 3:00–6:00, as you open (2). Don’t move beyond these points or the clay will be thrown off center and unequal walls will result.
1. Begin with a division of the mound: select the amount of clay you need for your form by creating a low point and a high point above it to segment the mound. If you’re going to use the entire mound for one large pot you may want to open in thirds.
2. Dispel any unwanted high points on the mound.
3. Throw down from the center corner of the lower right-hand quadrant, out to the point above the true base of the inside wall. That point varies with the amount of clay, and size of the pot you’re creating.
4. Roam and redirect: the outside hand roams to find the high point formed by the displaced clay. Surround the high point and fold to direct the clay in and up. When the high point is gone the extra clay has been dispersed into the wall. Roam with a delicate touch to find new emerging high points and again fold at the crest. Repeat until all displaced clay has moved into an equal thickness wall and the needed thickness remains in the floor.
5. Create the rim: move against the spin to throw clay into the waiting finger, receiving, sealing, compressing, and aligning particles to strengthen the rim.
6. Create the floor: when you’ve reached the maximum depth, leaving enough clay for an even-thickness floor, the height of the desired foot, and enough fresh clay move into the base of the wall with each pull, create the floor with a fish move (3), pressing and moving your fingers in toward the center at 2:00, then out from center toward 5:00 on the wheelhead, pausing at the true base of the inside wall.
7. Create the foot: the final thickness of the floor and the wall should match. Leave enough clay below the floor and throw an undercut to create a strong foot statement. The deepest point of the undercut should vertically align with the true base of the inside wall to facilitate even drying and structural integrity of the form.
Joyce Michaud is Professor of Art and Founding Director of the Graduate Ceramics Arts Program at Hood College in Frederick, Maryland.