What Is an Indirect Stencil?

Indirect stencils (or indirect photostencils) are a type of photographic stencil used in screen printing. They are unique in that they allow you to copy a detailed image onto a screen quickly and easily.

How They Work

The indirect stencil uses a stable film coated with a presensitized emulsion, synthetic polymer or gelatin. As indicated by the name, these stencils rely on an indirect method of adhering an image to the screen. An emulsion film (a light sensitive coated acetate film) is exposed with the art positive and then chemically hardened. The stencil is then cut into the desired shape and applied, using water, to the screen (usually a wire mesh), and then dried by heat.

Why Choose an Indirect Stencil

Indirect stencils are easy to use and allow you to produce high quality stencils quickly. They provide excellent resolution (picture clarity) and high definition (for example, straightness of lines). However, they are only usable for short run lengths, since they cannot provide more than 2,000 impressions.

Other Types of Photographic Stencils

There are also direct and direct/indirect photographic stencils.These are durable options for longer press runs. However, both of these types fail to match the picture quality generated by the indirect stencil.

References

• International Paper: Screen Printing
• Printers' National Environmental Assistance Center: Print Process Descriptions: Printing Industry Overview: Screen Printing