Screen printing is an art form that takes artwork from concept to wearable. While many believe it is a very complex and expensive process, the truth is that it’s pretty simple!
Once the screen is dry, cover it with a clean piece of glass to hold it in place and flip it over so that the non-recessed side is facing upward. Then, expose it to a light for the appropriate amount of time.
Ink
Screen printing is popular for promotional apparel items like T-shirts and fabric products. It offers versatility and precision, allowing for vibrant colours and fine details. However, before printing shirts for your customers, you must understand how the process works.
The first step in the screen-printing process is to prepare the screen with an emulsion sensitizer, creating the stencil. Master printers recommend choosing a sensitizer high in solids to prevent pinholes.
Once the emulsion is ready, you can apply the image to the screen with a squeegee. Block any areas you want to remain unprinted with water-resistant tape and use a heat press or Teflon sheet to protect the screen from damage during transfer.
Screens
Screen printing is the traditional method for creating shirts, posters, and other promotional items. It involves stencilling a design on a mesh screen and pressing ink (or paint, in the case of artwork and some prints) through a squeegee.
For starters, printers like A Thread Of Blue choose a mesh screen whose size and mesh density match the complexity of their design. They follow that by evenly coating the screen with a light-sensitive emulsion that will become rigid when exposed to intense light.
After the emulsion is dry, the printer tapes a positive film with their design onto the screen and places it in an exposure unit or light table. UV light then passes through the emulsion and creates the screen’s stencil. Finished screens are reclaimed for reuse once the emulsion has been destroyed.
Stencils
Using the stencil-making process, a light-sensitive emulsion is coated on the screen. An acetate sheet with the desired design is then placed over it and exposed to bright light, which hardens the parts of the screen that the emulsion has covered.
The acetate is then cut away, revealing the ‘holes’ that will later be filled with ink. The screen is then used to print the desired design on a product.
Expert screen printers can quickly turn out hundreds of items during a workday. When starting, however, investing in a quality manual press and building your printing skills is best. Many manufacturers also offer a variety of starter kits that provide the essential equipment to get started. They can range from basic ‘equipment-only’ kits to premium packages with everything you need to create your full-scale printing shop.
Substrate
Screen printing works best with garments that are 100% cotton and can be printed in multiple colours. The printing process involves creating a stencil for each colour used in the design on a delicate fabric mesh (the same material that makes up your favourite pair of yoga pants).
To create the stencils, screen printers use a light-sensitive emulsion. After the emulsion is exposed to UV light, it hardens, leaving a space for the ink to pass through. It is the same technique that is used to develop photographs.
Once the screens have been rigged to a print press, they can be loaded with the corresponding ink for each colour. Then, a squeegee is used to apply the ink. Once each colour has been applied, the prints go through a flash or conveyor dryer to cure them.
Cleaning
Screen printing is an effective method of transferring ink onto a substrate using a stencil. Ink is transmitted by using a blade (or squeegee) to touch the fabric or item where the stencil has been blocked. Only one colour is printed at a time.
After each print run, the screen must be properly cleaned. Cleaning the screen will prevent ink from leaking through areas of the mesh with no photo-sensitive emulsion and can help avoid image cracking. A solution of water and soap is typically used to clean the screen. Paint strippers are another option, but should be used in a well-ventilated area and with gloves. It is crucial to ensure that gentle fabrics are not subjected to harsh detergents that may cause harm to their material or colour.
