Screen Printing T-Shirts: A Step-By-Step Guide

Screen printing is a fun and inexpensive way to express your individual style by printing designs onto T-shirts. The process involves a few steps, starting with selecting a design and setting up the silkscreen. The silkscreen is then exposed to light, and the design is transferred onto the T-shirt using screen printing ink. Finally, the print is cured with heat to set the design. With some practice, you can create impressive results and even start selling your customised T-shirts.

Select a T-shirt design

Selecting a T-shirt design is a crucial step in the screen-printing process. Here are some detailed instructions and considerations to help you choose the right design:

Choose Your Artwork

The first step in selecting a T-shirt design is deciding on the artwork you want to print. You can either create your own artwork or have a customer provide it. Remember that the quality of the final print is heavily dependent on the quality of the artwork. If you're printing multiple colours, you'll need to separate the colours and create different screens for each colour in your design.

Use Graphic Design Software

To prepare your artwork for printing, you can use graphic design software like Illustrator, Photoshop, or Procreate. These programs will help you separate and clean up the artwork. If you're new to these programs, you can find many free courses and tutorials online to help you get started.

Print a Film Positive

Once your artwork is ready and the colours are separated, the next step is to print a film positive. This is similar to an overhead transparency, and you'll use it to burn the image onto a silk screen. Print whatever you want on the T-shirt onto the film positive using black ink.

Expose the Image onto a Screen

After printing the films, you'll need to make the screen. A screen printing frame consists of a wooden or aluminium frame stretched with polyester mesh. Coat the mesh with emulsion and expose the design onto the screen using a special lightbulb or exposure unit. This process will harden the screen, and you'll then rinse it with water to remove the unexposed emulsion, leaving your design on the mesh.

Choose Your T-shirt Material

When selecting a T-shirt design, consider the type of T-shirt you'll be printing on. Cotton is the ideal material for T-shirts as it's comfortable, soft, and breathable. Cotton blends and tri-blends are also good options as they're less prone to shrinking and are more lightweight.

Finalise Your Design

Before finalising your T-shirt design, you can customise it with graphics, text, or uploaded images. Get feedback from others by sharing your design via social media or with friends and family. Make sure your design is at least 220 PPI to ensure it doesn't pixelate when printed, and enhance it for CMYK printing to achieve vibrant colours.

By following these steps, you'll be well on your way to selecting a T-shirt design that is not only visually appealing but also technically prepared for the screen-printing process.

Set up the silkscreen

Setting up the silkscreen is a crucial step in the screen printing process. Here's a detailed guide on how to set up your silkscreen:

Workstation Setup:

• Choose a dimly lit room for your workstation to prevent UV light from prematurely hardening the emulsion.
• Cover your workstation with newspaper or an old sheet/tarp to protect the surface from chemicals.

Prepare Emulsion:

• Put on rubber gloves to protect your skin from chemicals.
• Mix emulsion and sensitizer according to the manufacturer's instructions. Use a disposable utensil for stirring.

Elevate Silkscreen:

• Place a pushpin into each corner of the flat side of the silkscreen (wooden frame covered with mesh) to elevate it.
• This will create a well for the emulsion.

Apply Emulsion:

• Pour 1-2 tablespoons of emulsion into the well of the frame.
• Use a squeegee to spread the emulsion evenly across the screen, applying gentle pressure.
• Rotate the frame as needed to cover all areas.
• Add more emulsion as needed, being careful not to use too much to avoid dripping.

Coat the Other Side:

• Flip the frame over and pour approximately 1 tablespoon of emulsion onto the flat side.
• Use the squeegee to spread the emulsion, ensuring a smooth coating.
• Remove any drip marks on either side of the screen.

Let it Set:

• Rest the screen on the pushpins and leave it to set overnight in a dim space.
• Speed up drying by placing a fan near the screen.
• If you need to transport the screen, cover it with a thick, dark fabric to block UV light.

Expose to Light:

• Place a transparency sheet (with your design) and a glass sheet on the flat side of the frame.
• Position a 250-watt light bulb about 18 inches above the frame to harden the emulsion.
• Expose the emulsion to light according to the manufacturer's instructions (typically 1 minute to 1 hour).

Rinse Emulsion:

• Spray the screen with cold water to remove the wet emulsion.
• Use a hose or showerhead to wash away the emulsion blocked by the design.
• Continue rinsing until your design appears as a stencil on the screen.

Dry the Screen:

Pat excess water with a clean cloth and let the screen air-dry for about 30 minutes or until completely dry.

Now your silkscreen is ready to be used for printing! Remember to test your setup on a piece of scrap fabric before printing on your T-shirt to ensure everything works as expected.

Expose the emulsion to light

Now that your emulsion has dried, it's time to expose it to light. This will involve placing your transparency sheet (with your design) and a glass sheet onto the flat side of the silkscreen frame.

First, ensure that the room you are working in is dim. Then, place the transparency sheet onto the centre of the screen. Layer a sheet of clear glass on top of the transparency. The glass will help keep the transparency sheet flat against the screen.

If your image is not symmetrical, lay the transparency sheet onto the screen so that the image appears backward. This is crucial for text-based images, otherwise, the image will print backward onto your shirt.

If you are planning to transport the frame outside to speed up the exposure process, cover the emulsion and the silkscreen frame with an opaque object, like a thick piece of cardboard or dense fabric.

Next, position a light source in the "off" position, above the layered frame. You can use any transportable lamp with a 250-watt light bulb. Move the light source so that it will spread light evenly over the screen—approximately 18 inches (46 cm) above the screen. The light will harden the emulsion that is not blocked by your T-shirt design.

The exposure time will depend on the brand of emulsion you are using and the light source intensity. It can take anywhere from 1 minute to 1 hour for the emulsion to harden. Generally, the emulsion will have a darkened appearance when it is fully hardened.

Once the emulsion has been exposed to light, quickly take off the glass and transparency sheet. Then, use a garden hose with a spray nozzle or a shower hose to remove the wet emulsion that was blocked by the design on the transparency sheet. Continue to spray the emulsion until a stencil of your design is visible on the screen.

If you need to take the silkscreen frame outside to hose it down, try to have the hose set up ahead of time. This way, the sunlight does not harden the wet emulsion that needs to be removed.

Finally, allow the screen to air-dry for 30 minutes before using it further. Use a clean cloth to pat excess water from the screen. Then, lay it flat and let it air-dry for about 30 minutes or until it is completely dry.

Prepare the screen

Preparing the screen for your T-shirt screen-printing process is a crucial step. Here is a detailed guide to help you through the process:

Start by gathering the necessary materials: a screen, emulsion, sensitizer, a scoop coater, a squeegee, and a screen printing exposure unit, such as a UV light source. The screen, typically made of silk or a synthetic mesh fabric, needs to be clean and free of any dust or debris. Use a gentle detergent and warm water to clean the screen if necessary, and allow it to dry completely.

Next, you will need to prepare the emulsion, which is a light-sensitive solution that hardens when exposed to light. The emulsion creates a stencil of your design on the screen. Mix the emulsion with a small amount of sensitizer, following the manufacturer's instructions. The sensitizer makes the emulsion more sensitive to light, ensuring that your design transfers accurately. It is important to work quickly and efficiently once the sensitizer is mixed, as it has a limited pot life.

Once your emulsion is ready, it's time to coat your screen. Place your screen on a flat surface, and use the scoop coater to apply the emulsion to the screen. Start at the bottom of the screen and work your way up, ensuring an even and smooth coating. Apply one coat, and for finer details or higher mesh counts, consider a second coat for better results. Allow the emulsion to dry completely in a dark room, or use a UV exposure unit to speed up the drying process.

After the emulsion has dried, you will need to expose your design onto the screen. Place your film positive or negative, depending on the emulsion type, onto the screen, and secure it in place. Ensure the image is correctly aligned and that the emulsion-coated screen is flat and taut. Expose the screen under a UV light source for the recommended time. This step is crucial, as it transfers your design onto the screen, creating a stencil for the printing process.

Finally, wash out the screen with water to remove any excess emulsion. The water will wash away the unexposed emulsion, revealing your design. Ensure that all areas of your design are washed out, and use a soft brush for any stubborn emulsion. Allow the screen to dry, and it will be ready for ink application and the printing process.

Transfer the design

Now that you have your design printed onto a transparency sheet, you can begin the process of transferring it onto your T-shirt. This involves several steps, including preparing your work area, creating a stencil from your design, and finally, printing your design onto the fabric.

Firstly, ensure your work area is covered with newspaper or another protective layer to prevent any mess or damage to your work surface. You will also need a light source, such as a lamp with a 250-watt bulb, positioned about 18 inches above your work area.

Next, you will need to create a stencil from your design. To do this, follow the manufacturer's instructions to mix emulsion and sensitizer. Then, place a silkscreen (a wooden frame covered with thin mesh) on top of four push pins to elevate it from your work surface. Pour 1-2 tablespoons of the emulsion mixture into the well of the frame and use a squeegee to spread it evenly across the screen. Flip the frame over and coat the flat side of the screen with emulsion as well. Allow the screen to dry overnight.

Once your screen is dry, it's time to expose the emulsion to light. Place your transparency sheet with your design onto the centre of the flat side of the screen, and layer a piece of clear glass on top to keep the transparency flat. Position your light source above the frame and turn it on, following the manufacturer's instructions for exposure time. The light will harden the emulsion that is not blocked by your design.

After the exposure is complete, remove the glass and transparency sheet and spray the screen with cold water to remove any remaining wet emulsion. Your design should now appear as a stencil on the screen. Allow the screen to air dry for about 30 minutes.

Now you are ready to print your design onto your T-shirt! Place a piece of cardboard inside your shirt to prevent the ink from bleeding through to the other side. Position the flat side of the screen against the front of your shirt, making sure the fabric underneath the screen is smooth and flat. Place a line of screen printing ink above your design, and use a clean squeegee to pull the ink across your design in a single direction. Continue until the ink is evenly dispersed.

Finally, remove the screen from the shirt and allow the ink to dry. Refer to the manufacturer's instructions for the best method to set the ink, such as ironing or exposing the shirt to sunlight. And that's it! You've successfully transferred your design onto a T-shirt using the screen printing method.

Frequently asked questions