The screen printing process is a very interesting, yet complex, way to create custom items. Here are the steps to how screen printing works. We hope that this information gives you some insight on our craft and how we strive to produce a quality product.
Step 1: Design creation
T-shirt designs work best with print-ready (vector) art. What does print-ready mean? Basically it means your artwork is set-up and ready to go for print without our designer touching it.
Vector art is created using vector illustration software programs, such as Adobe Illustrator or Corel Draw. These programs use points, lines, and shapes to create art that is clean, print-ready, and can be scaled infinitely, without any loss of quality.
If your art is print-ready, you upload your art, we send you a digital proof, you approve it, and we print it and deliver or ship. If your artwork is not “print-ready,” art charges could be incurred.
Once you have given your approval on the finalized artwork we begin the process of separating the colors in the design. Each color in the design is printed out on a film in solid black. One piece of film is needed for every color in the design. These films have registration marks on them that line up with one another to assist in lining up the screens on the printing press.
Step 2: Screen preparation
The printer chooses mesh screen to suit the complexity of the design, and the texture of the fabric being printed. Delicate or intricate designs may need a finer screen, like a 230, to capture the detail. The higher the mesh count, the finer the threads and holes are in the screen. Glitter inks have much larger particles so it would be recommended to use a 40 or 60 mesh screen. The mesh screen is then coated with a layer of light-reactive emulsion, which will harden when developed under bright light.
Step 3: The emulsion is exposed
The printed film featuring the design is then laid onto the emulsion-coated screen, and the whole thing is exposed to a very bright light. The light hardens the emulsion, so the parts of the screen which are covered by the design remain in liquid form.
If the final design is going to include more than one color, then a separate screen must be used to apply each layer of ink. To create multi-colored products, the printer must use his skill to separate each color in the design, and line them up perfectly (using the registration marks mentioned earlier) to ensure the final design is seamless.
Step 4: Rinse out the image, creating the screen image
After the screen has been exposed for a set time, the areas of the screen not covered by the design will have hardened. Any unhardened emulsion is then carefully rinsed away. This leaves a clear imprint of the design on the screen for the ink to pass through.
The screen is thoroughly dried, and the printer will make any necessary touch-ups or corrections to make the imprint as accurate as possible to the original design. The screen is now ready for use.
STEP 5: The press is loaded
The screen is taped so ink will not flow through any place but the actual design and then they are loaded onto the printing press. The item or garment being printed is laid down flat onto the shirt pallet which lies below the screen.
There are a number of different presses, including manual and automatic styles, but most modern commercial printers will use an automatic rotary carousel printer, which allows several different screens to work at once. For multicolored prints, this type of printer can also be used to apply the separate color layers in quick succession.
Step 6: The ink is pressed through the screen onto the item
The screen is lowered down onto the printing board. Ink is added to the top end of the screen, and a squeegee is used to pull the ink along the full length of the screen. This presses the ink through the open areas of the screen, imprinting the design on the product underneath.
If the printer is creating multiple items, then the screen is raised and a new garment is rotated to that part of the design for printing. The process then repeated.
Once all the items have been printed and the screen has served its purpose, the emulsion is removed (this is called reclaiming) using a special washing fluid so the mesh can be reused to create new screens.
Step 7: The product is dried, checked and finished
The printed product then passes through a dryer, which 'cures' the ink and creates a smooth, colorfast finish. The final product quantities are counted and checked by quality control before being packed for shipment or delivery.
Here is a cool video by one of the top screen printing press manufacturers, M&R, which shows a large press in action. https://www.youtube.com/watch?v=mku8Nt10Yr8&t=119s