In it’s simplest form, screen printing uses a porous, stretched woven mesh coated with an ink blocking material (typically emulsion) to create a stencil. Although the common terminology references the word silkscreen, actual silk has been long abandoned as a mesh material due to it’s cost. Modern day screens typically use nylon or polyester as a mesh material.
The stencil contains areas which are open, allowing ink to be passed through and deposited onto a printing surface (“substrate”). Typically, a flat, blade (“squeegee”) is moved across the screen to push the ink through the open areas of the stencil.
Although there are many ways to create a stencil, our focus for most of the tutorials and techniques will be on the creation of photo stencils. This is the most common method used in screen printing today and in my opinion, creates the best results. Photo stencils are created by coating the screen mesh with a photosensitive substance (“ photo emulsion”) that is sensitive to ultraviolet light. Exposure to a light source that contains the right wavelength of UV radiation (between 350-420 Nanometer) will harden the emulsion and block the holes in the screen mesh.
Placing opaque artwork on top of the photo emulsion during the exposure process will prevent the light from hardening the areas that are blocked by the artwork. After washing the screen, the areas that were not hardened in the exposure process will wash out, leaving open areas that ink can pass through.
If this sounds like a bunch of mumbo jumbo, here’s the laymen’s description of the process: You have a mesh material that is coated with a light sensitive, chemical substance. Light causes parts of that substance to harden. By blocking the light in certain areas, only parts of the substance will harden and the rest will wash out. This creates a stencil and we push ink through the open areas to create our printed designs.
In the series of tutorials that I’ll be posting, we’ll break up the process into the following categories:
- Materials and Supplies
- Setting Up a Work Area
- Creating a Film Positive
- Screen Preparation (prior to coating)
- Coating a Screen (direct film or capillary film)
- Exposing a Screen (various methods)
- Printing Techniques (paper or T-shirts)
- Reclaiming a Screen
- Troubleshooting
I’ll also be adding more posts for step-by-step projects, DIY Plans, screen printing on the cheap, reviews of products and also random posts about creativity, artists and whatever topics that are relevant to screen printing.
At this point, it may be a good idea to think about what you want to print, as it can determine the right strategy in terms of materials, studio set-up and equipment. Are you printing posters or T-shirts? Are they dark or light? Are you printing small greeting cards or bringing out your inner Warhol for large-scale canvas prints?
Keep the final outcome in mind as you read through these posts, as different substrates and different sizes require different strategies to execute properly.
