Monday, June 10, 2013

Introduction to Screen Printing

A couple of weeks ago, I had the opportunity to take the Introduction to Silkscreening class at TechShop. Silk screening and screen printing are almost equivalent terms for the art of using silk or synthetic screens stretched on frames to print designs on paper or fabric. Most of your t-shirts with designs on them were printed using a similar screen printing technique.  Silkscreening is a fantastic introduction to textile arts, even if you aren't much of an artist or a crafter.  The basic process is that you create a an inverse copy of your design on a screen through which ink can permeate with some sort of material that masks off parts of the screen and then you force ink through the vacant areas of the screen onto your material.  This leaves a copy of your design on the material.  Only one color of ink can be printed onto your material at a time

There are a few different ways to do screen printing that you'll encounter as an amateur. If you want one particular design that can be reproduced many times of the course of multiple production sessions, then you'll probably want to lay down your design on the screen using a photo-emulsion process.  This process uses a special material that is spread over the entirety of the screen and then the areas which you want to remain on the screen are exposed to light while the part that you want removed is protected from the light by one of several different masking procedures.  The extra emulsion is then removed from the screen, leaving a crisp, inverse copy of your design that will allow you to screen your design onto whatever material you want.  The key here is that the emulsion that is laid onto the screen can be washed and cleaned when you clean your screens of ink after printing without suffering any ill effects.  This process can be rather involved, since the process of laying down the emulsion, protecting it from light and creating a clean design can be challenging and requires more equipment.

A much simpler way to create just a few copies of a design, in one production session, is to cut your design out of a sheet of adhesive backed vinyl and to adhere that vinyl directly to the screen.  At TechShop, this can be done extremely easily because you have access to a CNC vinyl cutter. You have to take another class to use the cutter yourself, but during my silkscreening class, the instructor kindly cut out our designs for us. From there, it was a simple thing to remove the unnecessary pieces of vinyl from the design (a process called weeding) and to apply the vinyl to the silkscreen. In this way, you can make complex designs in a very precise way even if you have two thumbs like I do.  However, there's still the issue of transferring the vinyl without tearing it, not an entirely simply matter.

Once you've used one of these methods to mask out an inverse version of your design on the screen, you set up your frame in a special press that helps to hold your frames in place and you begin the process of actually applying ink to your material.  Although there is definitely some technique involved in applying the ink, and I didn't get it right until the third try, it is definitely doable for beginners.  You first flood your screen with ink with a squeegee before pressing the screen to your material, then apply the screen and run ink across your design two more times. Then you remove your screen and put your material under a drying lamp to fix the ink.

The process of screen printing your own designs onto a t-shirt or other material is not trivial even though it is rather simple and the results are very satisfying. Even though I had never done screen printing before, I was able to create and apply a design then take home a custom t-shirt after just a couple of hours! Although I can't say that I had ever had much of a desire to do screen printing before learning to do it, I'm now fascinated and want to cover all of my t-shirts in custom designs.  Of course I'll either need a TechShop membership or will have to make do at home with much more simple equipment.

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