screen printing questions...?

Question

allright, I'm about ready to try the photo emulsion technique for making up screens, and I have a couple of questions-
1.) Can I substitute tracing paper with the design drawn in with a black felt tip pen in place of the acetate (transparencies)? and
2.)If I make up a screen using photo emulsion, can I scrub it out later with Comet and a bristle brush like with the screen filler method, in order to re-use the screen for different designs, or is the screen permanent?

I'm using stuff from speedball's SP kit, according to their instructions, I can use tracing paper and the solution can be washed out within a month. I'm curios if anybody knows for a fact that this will work.

Answer 1

Tracing paper is a not a good idea the instructions should have said "tracing vellum paper" vellum is a special paper designed to allow light through. What light source are you using to burn the image? If you are using a natural light source then I would not attempt it. You can buy transparencies films from office supply stores that are clear and buy a opaquer pen as the felt tip will not be dark enough. Also the felt tip will bleed; lines will be fuzzy, on vellum.

You can clean the screen that way but man is that a lot of work. Make sure to break the comet down to a loose paste before putting in the screen. It is also good to scrub your screen down before using it for the first time to degrease the screen. Make sure to clean all comet out of the screen before using emulsion. The best way would be to soak the screen in water then scrub with comet as lightly as possible the pressure wash the image out of the screen. As scrubbing will scratch your mesh. I would not leave an image in your mesh for a month as you do not have the chemicals to remove the ghost image that will appear. After printing you must remove all ink from the screen. Tape the edges of the screen from the screen to the inside of the frame. This will make it so that the ink will not get into the edge between the screen and the frame, as that will change the next color you print with.

Tips: use a computer to make your graphics then put the graphics on the transparencies, laser works the best, make sure the transparencies are lying flat when curing emulsion as you should have a vacuum table to shoot the screen. Any gap between the film and screen will destroy your image.

Answer 2

Well I took screenprinting in college - but that was a long time ago. Honestly, I'm not sure about the tracing paper. I think the acetate blocks the light enough when you expose your screen where as the tracing paper may not. For the cleaning method...we used comet and a power washer. The emulsion get pretty hard after exposing and depending on how much ink you have left in it.

Answer 3

No you can not substitute the acetate, the tracing paper is cloudy and will block the light partially which will create extra soft parts that will washed away, damaging your art.

Yes you can reuse the screen using the comet or you can use bleach solution to soften the photo emulsion and wash it with warm water.

The tracing has to be opaque 100% in order to work properly.

If you want to experiment, use Potassium Bichromate (orange-yellow) with Elmer's glue, pour it over screen in a low light room, then let it dry in a completely dark environment, and follow instructions of photo emulsion technique.