How to Screen Print - 5 Reasons You Should Use Photographic Emulsion to Make Your Stencil

If you are screen printing as a hobby, you may have tried several ways to create your stencil. One such way that has been popularized on the internet is the screen fill method. Essentially, the screen fill method involves painting an image on a screen using a filler that dries and becomes your stencil. Once the stencil is created, the screen is used the same way it always is with screen printing: it is positioned on the fabric, ink is loaded into the screen, and a squeegee is used to push the ink through it. Wherever the holes in the screen have not been painted over, the image is created.

While some may consider the screen fill method simple and inexpensive, there are several drawbacks:

1. It is extremely time consuming, in fact most demonstrations of this method involve low detail, simple art.
2. When you make a mistake painting the filler, it can be quite aggravating to try to fix.
3. It is tedious.
4. If you want to reproduce the screen you have to do the whole process over again, and it'll never be exactly the same.
5. Line work and small type are pretty much out of the question.

Fortunately, there is another method for creating stencils on screens that solves all five of the above problems, and it is also relatively inexpensive on a per screen basis: the photographic method using light sensitive emulsion.

Basically, the photographic method involves filling all the holes in the screen with photographic emulsion (also know as coating the screen). A film is made with the desired image. The film has two parts to it, the light-blocking part and the transparent part. The film looks just like the final print will look, except it is black and clear.

The film acts as a light barrier when exposing the emulsion with light. The image on the film becomes the stencil on the screen, allowing the ink to pass only where the image is. Films are commonly made of transparencies on a paper much like tracing paper, or on specially coated acetate sheets that can be printed with an ink jet printer.

While there are a few types of photographic emulsions, including capillary films, diazo, photopolymer, and dual cure, the light sensitive emulsion that is probably the most useful to the kind of printer that might consider the screen fill method is the dual cure emulsion. The reason why the dual cure is a suitable substitute is because someone who would use the screen fill method most likely is looking to do a short print run if they are using waterbased inks(less than 1000 pieces), they want to make a quality screen that can be recycled, and they want as few steps as possible to create the screen with as little expense.

Coating screens with photographic emulsion is a fairly quick and painless process once you get the hang of it. While there are some best practices and trouble-shooting tips that can shorten your learning curve, even without much experience most people pick it up quickly. The one main drawback of the photographic process is that you need a light source to expose your screen. Fortunately, with the right set-up, you have a large variety of choices including the sun.