| Tools for teaching - A visual aids workshop, and instruction manual for health educators |
|Session 7. Project $3: Design/project #4: Planning 7.0|
|Handout 7.7.1 - A silkscreen manual (Supplementary learning materials)|
Blue film, the material from which silkscreen stencils are usually cut in the Philippines, isn't really blue at all, but grey. This translucent, lacquer-base film is supported by a light weight paper backing. When it is placed over the color separation on a light table or white background, the stencil cutter can easily see the keylines through the film.
The first-time stencil cutter needs to become familiar with the amount of pressure required to cut the film without going through the paper backing. Practice cutting on a small piece of film before tackling the actual stencil.
The steps in cutting a silkscreen stencil from blue film are as follows:
1) Tape color separation securely to work table. If the table is dark in color, place an opaque white backing between the table and the separation.
2) Cut a piece of blue film the size of the open area on your screen.
3) Center it, film side up, paper side down, over the color separation and tape securely to the table.
4) Using the point of an exacto knife with a #11 blade, carefully cut out each color area following the keylines on the color separation precisely.
REMEMBER: Don't press too hard. You want to avoid cutting through the paper backing. Be sure the entire outline has been cut cleanly and completely.
5) Use the edge of the knife blade to remove the film from those areas you want to print. This can be done by lifting an edge or corner of the film you want to remove just enough so that you can grab hold of the film with your fingers. Slowly peel the film away from the backing and discard.
6) After the stencil has been completely cut and all unwanted film peeled away, remove the tape and detach the blue film stencil from the table. Cover the stencil with the paper color separation and roll, film side in, to protect the image. Set the cut stencil aside until you are ready to adhere it to the screen.
7) Repeat this procedure with a fresh piece of blue film for each color separation.
NOTE: It is not always necessary to cut the stencil on blue film. Simple shapes can be cut from any waterproof material such as heavy plastic or exposed x-ray film and taped to the underside of the screen. You can even use heavy weight tracing paper provided you are not going to make too many copies. A gestescript or any other hand or typewritten stencil may also be used. With the possible exception of the x-ray film, none of these stencils can be reused.