What is screen printing? Screen printing is the process of using mesh to transfer ink onto a surface. First, a blocking stencil of an image or design is made on the mesh using emulsion and UV light. The emulsion makes areas impassable allowing only the stencil to come through the mesh. Then the screen print is left on a surface by using a squeegee and ink. The squeegee is moved across the screen to fill the open mesh with ink. This causes the ink to touch the surface and be pulled out of the mesh. One color is printed at a time, so several screens can be used to produce a multi-colored image or design.
As you can see, the process of screen printing is a long process with multiple steps. In this article, we explain each one of those steps in detail to guide you through the screen printing process. We also help you pick out the equipment needed for your screen printing shop.
Artwork for Screen Printing
The screen printing process all starts with when your customer submits their artwork or design to your screen printing shop. This artwork must be in vector format saved in outlines. If the artwork is not in vector format it must be converted to such by you or your graphics department. For multi-colored screen printing jobs, the colors must be separated out. This is so that one color can be printed at a time to produce your screen printing plates.
As a screen printer you’ll need to invest in Adobe Illustrator when dealing with vector artwork and separating out multi-colored print jobs. This vector graphic editor you can purchase as a yearly or monthly subscription through Adobe.
Once the artwork is ready you’ll then need to print it. Artwork is printed onto what is called waterproof inkjet transparency positive films which you can purchase here at Amazon. Designs are usually printed centered on the films along with registration marks to help align the artwork on the surface being printed. Transparency films usually have a smooth, slick side, and a textured/rough side. Make sure to print your design on the textured/rough side or sticky side of the film. You can test to see if it is the sticky side by wetting it with your finger.
The Making of Screen Printing Plates
In order to make screen printing plates, you’ll need eight components (two optional), including the transparency positive films mentioned above. The first one being optional is a wide format inkjet printer. If you don’t want to purchase one of these you can always have your films printed out at a place like Office Depot or Staples. Along with that, you will need a screen printing frame, mesh, emulsion, squeegee or emulsion scoop coater, UV exposure unit, and a yellow light bulb (optional) to make a screen printing plate. Here is a list if that makes it easier for you to follow.
- Wide format inkjet printer -optional
- Waterproof inkjet transparency positive films
- Screen printing frame
- Squeegee or emulsion scoop coater
- UV exposure unit
- Light safe dark room bulb -optional
To make a screen printing plate you’ll need to apply emulsion to your mesh using either a squeegee or a scoop coater. Either one will work, but preferably a scoop coater. Make sure to start this process in a dark room or with a light safe darkroom bulb, a yellow light bulb.
There are two sides to a screen plate a contact side and an inkwell side. The contact side is the bottom flat-surfaced side. And the inkwell side is the side where you place your ink once the screen is on the press. You’ll want to coat the contact side first. To dry lay the screen plate with the contact side down. This allows the emulsion to pull through the inkwell side onto the contact side. This fully encapsulates the screen.
Burn Your Screen
You’ll then need to take your film and place face down on the contact side so that you clearly see your image through the inkwell side of the screen printing frame. Usually, the artwork is centered on the mesh then move your artwork down from the top about a hand’s width away. Tape the film onto the mesh using clear tape. While you’re in a light safe room setup your UV exposure unit. Exposure time will vary depending on your setup, materials used, and consistency applying your emulsion. You can use an exposure calculator to determine burn times.
Your screen printing plate is now complete once you have burned your image onto the mesh. When working with multi-colored jobs make sure to place your artwork in the same place as your first screen plate to help align each color. You’ll need to do this by taking measurements.
Screen Printing Press Registration
Screen printing registration is probably one of the hardest jobs in screen printing. There are three ways to register your print job. First, you can register to the film. Second, you can register to the print. And third, you can use a pre-registration system. Here you can watch a video on how to setup press registration to ensure that your print is aligned properly. Registration of course, will depend on your setup and the press you have in your print shop. For instance, some print screen presses come with micro-registration and some do not. Make sure to follow these tips to register your press correctly for your screen printing job.
Screen Printing and Ink
There are three types of ink you can use for screen printing. Plastisol which is your most popular choice of inks. A water-based ink which is becoming increasingly more popular for its eco-friendlier nature. And discharge ink which gives you that soft-to-touch feel when printing on apparel. As a startup screen printer, I would probably purchase my ink with screenprinting.com. They have all three of these different types of inks available in their online store.
There are even PMS mixing systems you can buy in pints or quarts to get you going when mixing colors to color match. Speaking of color matching, you’ll need to have formulas to mix up and match your colors for printing. This can be done by using the formulas the ink suppliers have provided for you. An example would be, the Green Galaxy Fusion mixing system for water-based ink. Just simply provide the PMS code you are matching and how many grams of ink you plan to mix and use. The mixing system will then compute the formula and provide the ink you will need along with the amount of ink you’ll need when mixing.