It is always a bit of a challenge to get all over pattern onto a form with volume. But that didn’t hinder Forrest Lesch-Middelton. He was interested in covering the surface of his pots with intricate patterns inspired by the history of the Silk Road. So he decided to screen print his patterns onto a flat surface (newsprint and then transfer the design to a straight-sided cylinder. Then he shapes the pot into the volumetric shape he wants from the inside out. Pretty cool, eh?
In today’s post, Forrest gives a detailed description of his process. – Jennifer Harnetty, editor.
This technique was excerpted from a longer article
about the work of Forrest Lesch-Middleton in Ceramics Monthly magazine.
My work is planned layer-by-layer, both literally and figuratively. I start with an idea, a pot that to me has the feel of a weathered place prominent in my lifetime that has also stood the test of history. Once the layers and materials are chosen, the process begins with a pattern.
The patterns I use primarily come from the history of the Silk Road, which, to me, is a time and place in history that began to define the modern era. I fine-tune each pattern to a specific size and line density with the aid of Adobe Photoshop or Illustrator. By importing the image and adjusting color and contrast, I arrive at a black, photo-ready positive to be printed on a polyester laser transparency. The printed transparency is then laid over a light-sensitive photo silkscreen, exposed to light, and then washed out to create the final screen. When using ceramic materials as a screening medium, a 156-mesh screen is best. I order pre-exposed screens through a company in Vancouver, Washington, called Ryonet (www.ryonet.com). Send them an image, they send you a finished screen.
When printing with ceramic materials, it is important to use a printing medium compatible with the ceramic process. For colors, I use straight Crocus Martis, a naturally occurring 50/50 mix of black and red iron oxide, because it suits the very specific aesthetic needs of my work. You can use any ceramic oxide or stain.
The trick to my surfaces lies in transferring the image from the screen to the clay. For that you need a screening medium and some 25–30 pound newsprint. The recipe that I have found works best for a screening medium is a thick, white slip that is deflocculated to the consistency of sour cream. Deflocculating the slip allows it to become fluid with a smaller percentage of added water, which means it will not saturate or break down the newsprint when screened, and dries to a usable state more quickly. For color, add stain to the slip, mix it, and sieve through a 160-mesh screen. Next, add wet wallpaper paste (a starch-based glue that adheres the screened image to the newsprint) at a ratio of one-fifth the total volume of the slip. I have found that Roman’s brand wallpaper paste for unpasted wallpaper works best because you can pour it straight from the jug into your screening medium. Once mixed, place a line or bead of the medium at the top of your screen and press it through onto a piece of newsprint using a printmaking squeegee. Once the image is on the paper, it only needs 20 minutes or so to dry and it is ready to use. When the transfer is re-wetted at a later time by painting a slip over the surface, it is able to stick to another surface (think temporary tattoo)!
In order to get each pattern to register around a thrown cylinder correctly, I have found junior high school geometry (like circumference = Pi × diameter) comes in handy. First, tear or cut the pattern so that the pattern lines up correctly when wrapped end-to-end into a cylinder. Next, measure the length of the pattern with a metric ruler. This measurement will be the circumference of your cylinder. Once the image is measured, divide the total length by 3.14 and round down to get the diameter of the cylinder. For example: 33 cm/3.14=10.509, or 10.5 cm. Set your calipers to 10.5 cm and you are set to throw a cylinder. Each cylinder should be completely vertical and exactly 10.5 cm across.
Coat the freshly-thrown cylinder with the plain deflocculated slip using a hake brush. The deflocculated slip will dry more quickly, and will not add as much water to the form as a regular slip.
This speeds up the drying process, allowing you to add the transfer sooner for more productivity. When the cylinder is coated evenly with the slip, coat the newsprint transfer on the side that contains the image. Once both surfaces are tacky to the touch, lift the newsprint off the table and stick it to the pot by wrapping it around the surface end to end, trying not to trap air bubbles (students say that this is the trickiest part). Use a flexible metal rib to adhere the newsprint gingerly to the cylinder with vertical strokes, starting at the bottom and moving upward. Once attached, peel off the newsprint and your image is transferred to the cylinder.
Once the image is in place it should not be touched or agitated in any way or it will smear. In order to add volume to the image-laden vertical form, you must belly the pot out from the interior. One issue that arose for me in working this way was the amount of torque that a wheel puts on the soft clay cylinder while it is spinning. To eliminate too much twisting, I carefully monitor the pattern while the pot spins, watching for twists. As a twist occurs in the pattern, I simply begin to spin the wheel in reverse and further belly out the form to counteract the distortion.