Minter and Barrett began experimenting, using masking tape to block out areas of the fabric surface, or sha, of a Japanese mould. This left thin areas in the finished sheet that would tear easily. Some of the tape lifted when they made test sheets, but enough of it stayed in place to show them that the idea would work. They found that long-fibered, high quality kozo was the most effective in bridging the open spaces of the patterns and making a strong finished sheet. Later, Barrett used a photo-sensitive emulsion, normally used in screen printing, to create a more stable sha. This same sha has been used at the Paper Facility during every winter papermaking season for over ten years.1 Traditionally, shas are a fine silk fabric attached to the bamboo su for making thin, delicate "wove" Japanese paper, free of the su's laid and chain lines. Before it is attached to the su, the sha is treated with fermented persimmon juice to toughen and stiffen the fabric. It will lay flat during sheet forming but remains flexible during the rolling action of couching. In early 1997 I looked into making additional shas for the Paper Facility and some for my own use. I developed various new methods for making patterned shas that I would like to share. Finding the right fabric for the sha was my first step. The fabric had to have an open weave, to allow water to drain, but still be fine enough to keep individual paper fibers from passing through. Years ago, Barrett was able to find 2XX silk fabric used in screen printing, but this is no longer available. The only screen printing fabric I could find was a 6XX polyester. This turned out to be the most successful fabric for the shas I made. I also tried chiffon and window shear, a thin drapery fabric. All of these are thin, have very soft drapes, and need to be stiffened to hold their shape in water. Since fermented persimmons are not available in my neighborhood, I used thinned polyurethane varnish.2 To apply the varnish and to aid in the other steps of making the sha, I needed to stretch the fabric over a frame. I made a wooden frame several inches larger than my finished sha dimensions (pre-made stretcher bars would have worked, also). Then I stretched the fabric evenly, to avoid distorting the weave, and stapled it to the frame. I mixed one part varnish to two parts mineral spirits. Using a rag, I wiped the surface with long, even strokes. Then, with a dry cloth, I wiped off the extra solution so that the openings between the threads were not blocked. This would have caused drainage problems later. When the surface was dry, I applied a second coat. If I had wanted a plain sha, I would have removed the fabric from the frame at this point. To make a sha for patterned or decorative papers, I needed to block out parts of the screen. I could do this simply and most directly by painting out areas with acrylics while the fabric was still stretched on the frame. I had to apply several coats to block out the openings in the weave. I had initially tried using pre-cut plastic stencils sold for decorating walls. I taped the stencil in place and used a stenciling brush to dab the paint onto the screen, but it was difficult to get a heavy enough layer without having some paint ooze under the stencil. I had more success when I used a light coating to outline the pattern, removed the stencil, and filled in the rest by hand. Patterns with thin lines, no more than an eighth of an inch thick, work the best. One sha I made using acrylic paint had both large areas and thin lines blocked. The wide areas gave me problems during sheet forming, especially during couching. The paper fibers did not span the open areas as well as they spanned the thin lines, and this left holes in the large areas. During couching, these openings would not release from the su and the edges tore easily. Since I wanted to use this sha, a simple solution was to make a double-layered sheet. Using two separate vats and another su, I made the first layer a plain sheet and couched it on a piece of interfacing material (called Pellon). I used the patterned sha in a vat of dyed kozo and couched it over the first sheet. Because the base sheet was solid, it supported the patterned layer and the couching was easier, although the edges of the openings still occasionally tore or rolled over on themselves. I put down another piece of interleaving before I made the next sheet, much as felts are used in Western papermaking. Another method that I tried for creating patterns was screen printing directly on the sha fabric. Like the pre-cut stencils, the layer of ink did not fill the openings in the fabric and I had to paint over it by hand. A student at the University, Anna Embree, tried using iron-on interfacing to block selected areas. Using the thinnest interfacing, she cut strips and ironed them onto the fabric. It worked well, but we do not know how long the adhesive would last with heavy use. Using Barrett's sha as a model, I also experimented with photo emulsion to create the patterns. I could not find the emulsion Barrett had used, called One Pot Sol. A screen printing company recommended Croma/tech PL instead. This emulsion requires specialized lights for exposure, but I was told that I could use common grow lights, made for plants. The emulsion needs to be applied to the fabric in a darkroom under a safe light. The exposure time ranges only from one to two minutes, leaving little margin for error. I tried to make a clean image several times, changing the exposure time and adding another light. The results gradually improved, but I was experimenting with only a small sha, about thirteen inches wide, and I needed to be able to make thirty-six inch wide shas for the Paper Facility. When a friend offered me an old screen printing kit that included a bottle of Speedball Diazo photo emulsion, I tried it. It worked better than Croma/tech PL and was easier to use. The emulsion can be applied to the fabric in a lighted room and then dried in the dark. A regular 100-watt light bulb can be used and the exposure time is an hour or longer, leaving less chance of over- or underexposure. Speedball brand emulsions are found at many art stores. A piece of card stock worked well for applying the emulsion to the fabric but for larger shas a scoop coater, used in screen printing, worked better. I tilted the stretched sha at a 45 degree angle and poured the emulsion onto the screen. Holding the card perpendicular to the fabric, I spread the emulsion with long strokes and repeated the strokes on the back of the fabric. I found that the emulsion began to dry out and pull away from areas if I overworked it. I laid the frame with the sha flat and put blocks of wood under the corners so the fabric would not touch the table if it sagged. Then I let it dry in a completely dark room. To use the photo emulsion, I needed a stencil that would block out light in the areas where I did not want the emulsion exposed. A common product for masking is Rubylith, a red film layer backed with Mylar. The red layer blocks out light so I cut and peeled it away where I wanted the emulsion exposed. This film worked well for straight cuts and lines. I made another stencil by photocopying a drawing onto clear Mylar. I taped together two copies so the black areas would be dense enough to block out the light. I then held the copies together against a window to find any thin areas so I could fill them in with a black marker. The biggest limitation of this method was the 8" x 11" format, the largest photocopy my local copy shop could make. (Photography stores and some copy shops can make larger positive images, but they cost more.) When setting up for the exposure, I used a light fixture with a reflecting bowl. As an inexpensive alternative, I could have cut an opening in a foil pie tin and slipped it around the bulb. I hung the light about twelve inches above the screen (higher for large screens). I used a 150-watt bulb (a no. 1 photoflood 250-watt bulb would have also worked). The emulsion comes with suggested exposure times, but I sometimes had to try several times with different exposures to get a clean image. I found that I needed a foam pad, a piece of blanket, or some other soft cloth to fit inside the opening on the sha frame. I laid the sha frame over this pad, then put the stencil down and laid a piece of glass on top. This kept the stencil in direct contact with the emulsion and the fabric during exposure. After the sha was exposed, I took it to a sink and gently sprayed it with warm water. I used a garden hose but one could use a sink sprayer or shower sprayer instead. In a few minutes, the image area started to appear as the unexposed area washed away. Whenever the exposed area began to lift or wash out, I started again with a new screen and tried a longer exposure. After the fabric was dry, I cut it out of the frame and trimmed it roughly to size. Water causes the bamboo of the su to swell. If the sha is secured to a dry su, it may become distorted when the su later gets wet during papermaking. To avoid this, both the sha and the su should be wet when they are sewn together. I soaked them for about fifteen minutes, then aligned the two, lifting them out by holding the fabric along one of the support sticks of the su. I lifted them together to prevent air bubbles from being trapped between the two. I laid them on a table and sewed along one of the support sticks with whip stitches, starting and ending with a double stitch and a knot along the back of the su. Then I trimmed the sha to the finished size. I also finished the edges with a product called Fray Check, a waterproof glue available from fabric supply stores that keeps cut fabric from fraying. Now the new sha was ready to use. I made my sheets from a Japanese green bark kozo. I had to make the paper thin so the image would be clearly visible in the finished paper. When I made strips to be torn apart, like the MDTGS, the rocking action in forming the sheet needed to be in the direction of the strips. For other patterns, sheets could be formed with both front-to-back and side-to-side action. When couching the sheets, I staggered them slightly (by about one eighth inch) so that the thick and thin areas of the pattern overlapped. This made the post more stable. When I made a small amount of paper, I used interfacing between the sheets. For double-layered sheets, I used interfacing between each pair of sheets to make separating the pressed sheets easier. In the end I made several small shas and have made paper on all of them. The finished paper is the final judge and I will have to make a few of the shas again. On one of the striped shas the blocked out areas were too thick. The fiber could not bridge the gap and the strips tore into pieces when I tried to dry them. The experiments I tried were helpful in developing the shas but I ran out of time. I ended up not making new shas for the University of Iowa's Paper Facility. Nevertheless, I hope this article helps others make patterned shas for their own work. Notes: 1. A description of the development of this sha is found in the Spring 1986 (Volume 1, Number 1) issue of Hand Papermaking, on pages 7-9. 2. A more complete description of making shas can be found in Japanese Papermaking Traditions, Tools, and Techniques by Timothy Barrett (Weatherhill, New York & Tokyo, 1983) on pages 116-118.
