The Art Of T-Shirt Screen Printing: A Step-By-Step Guide

Screen printing is a popular method for printing designs on T-shirts. The process involves using a mesh screen to transfer a stencilled design onto the fabric. The screen is stretched over a wooden or aluminium frame and then coated with emulsion. After the emulsion has dried, the design is burned or exposed onto the screen. Ink is then pushed through the screen onto the T-shirt using a squeegee or rubber blade. Screen printing is a versatile and cost-effective method for printing T-shirts, allowing for bold and vivid colours, as well as intricate and multicolor designs.

Screen printing frame construction

Screen printing is a complex process that requires a carefully constructed frame to ensure a successful print. The frame is a crucial component, as it holds the mesh that will be used to transfer the ink onto the T-shirt.

A screen printing frame consists of a wood or aluminium frame stretched with polyester mesh. The mesh needs to be taut and free of any dust, lint or particles, so it is important that the frame is constructed to be durable and able to withstand frequent use.

Wooden frames are a popular choice for screen printing and are available in a range of sizes. They are typically made from top-grade wood, which provides exceptional durability and resistance to corrosion. The wood is carefully selected to be safe and non-toxic, ensuring a comfortable and secure handling experience.

Aluminium frames are another option and offer a lightweight alternative to wooden frames. They are often used in larger sizes and can accommodate higher mesh counts, which is useful for printing finer details.

When constructing a screen printing frame, it is important to ensure that the corners are precisely mitered and fastened securely. This ensures a perfect fit for your printing needs and prevents any ink from escaping from the sides of the frame.

In addition to the frame construction, choosing the right mesh is also crucial. The mesh count, or threads per inch, will depend on the detail and complexity of your design. For printing T-shirts, a lower mesh count, such as 110 or 120, is typically suitable. However, for designs with finer details, a higher mesh count may be required.

Stencil creation

Creating a stencil usually begins with designing the artwork to be printed. The quality of the artwork will determine the quality of the final print, so it is important to start with a good design. If multiple colours are used, each colour must be separated and placed on a different screen.

Once the artwork is created, the next step is to print a film positive. A film positive transparency is like an overhead transparency, and it is used to burn the image onto the silk screen. The film positive is printed in black ink and can be created by a local print shop, hand-drawn, or printed with a compatible printer.

After the film positive is created, the screen printing frame is prepared. The frame consists of wood or aluminium with polyester mesh stretched over it. The mesh holds the image and allows ink to pass through when pressed with a squeegee. Before coating the mesh with emulsion, it must be cleaned with a special screen printing degreaser to remove any dust, lint, or particles that could affect the emulsion.

Emulsion is light-sensitive, so coating the screen is typically done in a darkroom with special light-safe yellow bulbs. After the screen is coated and dried, the film positive is aligned on the screen and exposed using a screen printing exposure unit or an exposure lightbulb for a set amount of time. The screen hardens where the light hits it, but the film positive or black area of the film blocks light from reaching the emulsion. This leaves the area of emulsion underneath the design soft. After exposing the screen, it is rinsed with water, and the soft part of the emulsion that was not exposed is washed away, leaving a space in the mesh in the shape of the design.

Ink application

The ink is then dried and cured using a dryer or flash dryer. The temperature at which the ink cures varies, so it is important to read the instructions on the ink container to ensure the correct temperature is used. If the shirt is not cured properly, the ink will not last, and the print will degrade.

Once the ink is cured, the shirt is inspected to ensure it looks exactly like the mockup. The ink will have a raised feel to it due to being placed on top of the fabric.

Printing

Screen printing is a process that involves pushing ink through a mesh screen to transfer a design onto fabric or paper. The process is also known as silk screening or silk screen printing, and while the actual printing process is always fairly similar, the way the stencil is created can vary depending on the materials used.

Step 1: Create a design

Firstly, you will need to create a design that you want to print onto a T-shirt. This can be done using software such as Illustrator, Photoshop, or Procreate. The better the quality of the artwork, the better the quality of the screen print.

Step 2: Prepare the screen

Next, you will need to prepare the screen by coating it with a layer of light-reactive emulsion, which will harden when developed under bright light. The type of mesh screen used will depend on the complexity of the design and the texture of the fabric being printed.

Step 3: Expose the emulsion

Once the emulsion has been applied, the acetate sheet featuring the design is laid onto the screen and the whole thing is exposed to a very bright light. The light hardens the emulsion, so the parts of the screen covered by the design remain in liquid form. If the design includes multiple colours, a separate screen must be used for each colour.

Step 4: Wash off the emulsion and create the stencil

After the screen has been exposed for a set time, the areas of the screen not covered by the design will have turned hard. Any unhardened emulsion is then carefully rinsed away, leaving a clear imprint of the design on the screen for the ink to pass through. The screen is then dried, and any necessary touch-ups are made to ensure the imprint is accurate.

Step 5: Prepare the T-shirt for printing

The screen is then placed on the printing press, and the T-shirt is laid down flat onto the printing board underneath the screen. It is important to ensure that the T-shirt is clean and dry, and that there are no wrinkles or creases that could distort the design.

Step 6: Press the ink through the screen onto the T-shirt

The screen is lowered down onto the printing board, and ink is added to the top end. A squeegee is then used to pull the ink along the full length of the screen, pressing it through the open areas of the stencil and imprinting the design onto the T-shirt. If multiple items are being printed, the process is repeated for each one.

Step 7: Dry, check and finish the T-shirt

The printed T-shirt then passes through a dryer, which 'cures' the ink and creates a smooth, colourfast finish. The final product is checked and washed thoroughly to remove any residue before being passed on to its new owner.

Drying and curing

There are several methods for drying and curing screen-printed T-shirts, each with its advantages and disadvantages. Here are some of the most common techniques:

Air Drying

This method is the easiest and most straightforward way to cure T-shirts printed with water-based inks. It involves hanging or racking the T-shirts and, optionally, using a fan to create airflow and expedite the drying process. However, it may not be the best method, as it can take up to 48 hours for the ink to fully cure, and there is a risk of smudging if the fan is aimed directly at the T-shirts.

Oven-Baking

While it may sound unconventional, curing T-shirts in a kitchen oven is possible. However, it is not recommended due to the risk of burning the garment and releasing chemicals that can be hazardous to health. Ovens often struggle to produce constant and even heating, leading to inconsistent curing.

Using an Iron

Using a standard iron is another inexpensive way to cure screen-printed T-shirts, especially for smaller designs like logos or symbols. Irons can reach temperatures of up to 350–400°F, but their small surface area limits their effectiveness for larger designs. Additionally, there is a risk of scorching some areas of the fabric while under-curing others.

Hair Dryer

Using a regular hair dryer is a popular choice among DIY screen printers. It is convenient and safer than an iron, but it is not ideal for high-temperature curing. Commercial hair dryers typically max out at 100–140°F, making them unsuitable for plastisol inks. They can be used for water-based inks, but it will take a long time to reach the desired curing temperature, and there is a risk of ink bleeding due to the rapid air blowing.

Heat Gun

Heat guns are a popular budget option for curing ink on T-shirts. They are portable and can reach temperatures of up to 1200°F. However, curing larger prints or batches of T-shirts with a heat gun can be time-consuming, and it can be challenging to maintain consistent heat across the entire print. There is also a risk of scorching the garment if the heat gun is held too close.

Halogen Lamp

Halogen lamps emit higher levels of UVB and have wider coverage than spot heating methods like heat guns and hair dryers. A 300-watt halogen lamp can instantly reach temperatures of 1000°F, making it suitable for curing both plastisol and water-based inks. They heat up quickly and are relatively portable, making them a versatile option for curing, exposing, and flashing.

Heat Press

The heat press is a stable heat source commonly found in screen-printing facilities. It works with both plastisol and water-based inks and is excellent for gelling, flashing, and curing T-shirts. Heat presses provide accurate temperature readings and often include timers and pressure gauges to ensure consistent results. They are ideal for lower-volume shops as they cure one piece at a time but offer precision and reliability.

Flash Dryer

Flash dryers are commonly used by screen printers, especially those starting in the business. They are compact, relatively inexpensive, and more consistent than heat guns. They use large bursts of intense, concentrated heat to cure the ink and are simple to operate, making them a favourite among beginners.

Conveyor Dryer

Conveyor dryers are the biggest and most expensive curing method, typically found in brick-and-mortar screen-printing shops. They are used for high-volume orders, running multiple shirts through at once to speed up production. Conveyor dryers can cure both water-based and plastisol inks and offer forced air circulation to enhance the curing process.

Frequently asked questions