Let’s take a quick walk through the entire process.
In a Nutshell
- Completed art is laser printed on a film
- Image on the film is burned onto a silk framed screen
- Screen is washed to remove only portions of the image from the screen
- Screens are attached to a press
- Multiple colors from the art require the screens to be registered/aligned
- Ink is squeegeed onto the garment
- The ink on the garment is dried and cured
To start any screen print order, we begin with your artwork or your vision. We will either receive your artwork, create it for you, or more likely, some combination of the two. Most of our customers have little understanding of what kind of artwork we need, or what we are capable of reproducing on a garment. We prefer Corel Draw files (.CDR), but we also work with Adobe Photoshop (.AI) files, PDF’s, JPEG’s, PNG’s and even scanned photos. Don’t be afraid to talk to us about your ideas since we can even work from a pencil sketch!
If your artwork has multiple colors, we have to separate the colors to create an image with only one color. With the colors separated, we occasionally have to manipulate the size of a color, while considering which colors will be applied in what order so that they overlap.
Once the artwork is finished and you have approved it, we create a film positive(s) by laser printing it onto an acetate film(s).
Screens are framed with wood or aluminum. A silk screen is stretched across the frame and secured. The silk screen comes in various mesh and must be selected for the specific art or amount of ink we want to allow onto the print.
To make a screen ready for the press, we need to apply a photo-sensitive emulsion to the mesh. We apply a liquid emulsion to both sides of the screen using a scoop coater. This hand-held device is filled with emulsion, placed against the screen mesh and slowly pulled bottom to top, depositing emulsion as we go. The screen is then turned and the same process is repeated on the other side.
The emulsion on the screen then has to dry, and is stored in the dark.
Exposing the screen
We place our film positive against the emulsion coated screen, and place it in our exposure unit.
The exposure unit has a rubber membrane and vacuum pump to ensure the image is tight against the screen. We then expose the screen to UV light. Where the light touches the screen, the emulsion hardens. Where the light does not touch the coated screen (behind the black parts of our artwork), the emulsion stays soft. After exposing the screen to UV light, we remove the film positive and wash out the image with a gentle spray of water. The screen is then air-dried.
Depending on your order size and number of screens (colors in your art), we’ll likely use our manual press for smaller orders (30 or so pieces). For larger orders we’ll use our automated press that enables us print about 1400 shirts per day.
The screen(s) are secured onto the press and adjusted so that the image is properly positioned on the garment. For multiple screens (colors), each screen must be micro adjusted so that each color is registered (properly aligned) to all other screens. This can be a tedious process, but ensures there are minimal voids between colors.
We primarily use plastisol ink. If you have any printed T-shirts in your dresser drawer at home, they are likely printed with plastisol. Plastisol will not air dry and has to be heat cured. Some ink requires the mixing of additives to produce a desired effect or for proper adhesion to various garments. It may also be necessary to mix colors to meet a customer’s specific requirement or it may simply be a color that we don’t have in stock.
Squeegees are most commonly wood handle and a square plastic or rubber blade. Squeegee blades come in different hardness. Softer squeegees will lay down more ink, and harder squeegees lay down less.
A low tack adhesive is used to lightly hold the fabric onto the shirt platen.
After the ink is squeegee’d onto the garment, the inks will need to be heat set. White ink is almost always “flashed” cured while the shirt/garment remains in position on the platen. When the print process is complete, the garment is removed from the platen and placed on our conveyor dryer, ultimately reaching 320 degrees. When the shirt exits the other end the garment is finished. You can wear it, wash it, fold it and box it. Once plastisol ink reaches curing temperature, it is completely cured, now and forever.