Different Types of Screen Printing Techniques

Screen printing, also known as silkscreen printing, is a popular printing technique used to create custom t-shirts, posters, and other promotional materials. The basic process involves using a mesh screen to apply ink onto a surface. While the fundamentals are straightforward, there are several different screen printing techniques that can be used to achieve different looks and effects. In this comprehensive guide, we will explore the most common types of screen printing and how they work.

Overview of Screen Printing

Before diving into the various techniques, let‘s briefly go over the screen printing process itself. The basic steps are:

1. Create the design: The design is created digitally using design software. The number of colors dictates the number of screens needed.

2. Prepare the screens: A taut mesh is stretched across a frame to act as the template. A UV light-sensitive emulsion is applied to the screen.

3. Burn the screen: The design is printed onto a transparency and placed on the screen. UV light hardens the emulsion not covered by the design.

4. Wash out the screen: Water washes away any emulsion left uncovered. Ink will pass through the bare mesh but not the hardened emulsion.

5. Add ink: Ink is placed on top of the screen and pushed through the mesh using a squeegee. The ink passes through to print the design.

With the screens prepared, it‘s time to explore the various printing techniques that can be used.

Spot Color Printing

Spot color printing, also known as solid color printing, is the most common screen printing technique. It uses custom-mixed inks to produce vibrant, opaque colors on light or dark colored garments.

With spot color printing, each color in the design requires a separate screen. For example, a two-color design needs two screens, one for each color. The first color is printed, then the garment is lined up again and the second color applied. This layering of the inks allows you to achieve crisp, bright colors.

The advantage of spot colors is better ink opacity and color consistency compared to process printing. The inks can be mixed to precisely match any Pantone color. Spot color inks also fully saturate the garment, leading to a thicker print with a smooth feel. The downside is that a separate screen is required for every color, increasing costs.

Spot color printing is ideal for simpler designs, especially those using one to four colors. It‘s also preferred for printing darker garments where ink opacity is important. If photorealistic quality isn‘t necessary, spot colors remain the go-to choice for custom t-shirts.

Simulated Process Printing

Simulated process printing aims to simulate the full-color printing possible with process colors using spot color inks instead. This helps reduce costs while still providing some photorealism.

The standard process colors are cyan, magenta, yellow, and black (CMYK). But with simulated process printing, spot color inks are carefully chosen and printed in layers to try and recreate these process colors optically.

For example, a vibrant red and royal blue ink could be mixed to simulate the full gamut of colors necessary. These spot color inks are still opaque, providing better saturation and consistency than CMYK process printing.

The separator software uses different screen angles and dot patterns to combine the spot color inks and trick the eye into seeing other colors. This optical mixing of the inks can closely mimic process color printing at lower costs by reducing the number of screens required.

Simulated process printing provides much better photorealism than spot colors alone. And it remains significantly cheaper than true process color printing. The tradeoff is that the color gamut is smaller compared to process printing. But the improved opacity and saturation of spot inks make up for this limitation in many cases.

Process Color Printing

Process color printing refers to reproducing full-color photographic images on garments using the standard four process color inks: CMYK (cyan, magenta, yellow, and black). It works by separating the design into four halftone films to apply the CMYK inks as tiny dots in different combinations.

This printing technique allows for near-continuous tone photorealism since the dots and small variations in ink density can create millions of apparent colors. The white of the garment mixes with the transparent process inks to produce the full spectrum of hues.

So while process printing provides exceptional realism capable of reproducing photographs, the tradeoff is that the prints feel lighter and less opaque. Only a thin layer of ink is deposited on the surface. The white garment background shows through much more compared to opaque spot color inks.

Process color printing also tends to have more inconsistencies between prints because slight variations in the dot size and ink density change the final mixed colors. Registering the separate color screens precisely is paramount but difficult. Still, process color screening delivers photorealism not possible with spot colors alone.

It‘s important to note that process color printing only works well on white or very light colored garments. Because the colors mix optically, darker garments will tint the results, preventing accurate color reproduction.

Discharge Printing

Most screen printing techniques we‘ve covered so far work by depositing ink onto the garment. But discharge printing takes the opposite approach – it removes dye from the fabric rather than applying it. This dye removal technique can create a distressed or vintage look.

Discharge inks contain chemicals that sever the bonds holding the dye molecules to the fabric. Water washes these released dyes away. So rather than adding white ink to create a faded effect on a colored shirt, discharge printing removes the original dye.

There are two main types:

Full Bleach Discharge: All color is removed in the printed areas, leaving white.

Color Discharge: Removes color only partially, tinting the printed section.

Discharge styles work best on cotton fabrics where the dyes permeate the material. The results can seem like a fading, worn-in shirt right off the press. It yields exceptional softness since no ink coats the fabric. And the technique introduces striking contrast between the printed discharge areas and the normally dyed garment.

The limitations are that discharge inks require higher curing temperatures to activate the bleaching, putting greater stress on the garment. And discharge printing doesn‘t work well on polyester or blended fabrics where the dyes only coat the exterior. But the unique faded effects possible make discharge printing popular for vintage and distressed print styles.

Water-Based Ink Printing

Traditional plastisol inks used for screen printing contain PVC resins and require high heat curing to fix permanently to textiles. But printers also have the option of using water-based inks. As the name suggests, these inks use water as the carrier rather than petroleum-based solvents.

Water-based inks provide a softer feel and reduced environmental impact compared to plastisol. They contain far fewer volatile organic compounds (VOCs), making them safer to work with. Since they air dry, high-temperature curing isn‘t necessary either.

The tradeoffs are that water-based inks produce a thinner print with less opacity. They are also less durable, flexible, and abrasion-resistant than standard plastisol. But improvements in formula and chemistry continue to close this performance gap.

For printing onto darker garments, an underbase white ink is often still required to prevent transparency issues and build density. The water-based inks sit on top of this underbase layer.

Common applications for water-based inks include printing onto fabrics where a softer hand is desirable, like infant clothes or athletic apparel. They also work for environmentally-friendly printing onto canvas bags, organic textiles, and other items where durability isn‘t critical.

Foil Printing

Foil printing provides eye-catching metallic and glitter effects by adhering foil material to clothing. The foil sticks to deposited ink, allowing selective application.

The printing process starts the same way by using standard screens and plastisol or other ink. This ink acts as the adhesive layer. The foil sheets are then carefully placed over the wet ink prints and run through a heated press.

The combination of pressure and heat causes the foil to firmly bond to the ink. Peeling back the foil leaves the metallic material stuck only where the adhesive ink was printed.

Holographic foil sheets offer rainbow reflection effects. Other options include imitation gold, silver, copper and more. This specialty printing technique catches the light for stand-out shine unachievable with standard inks. Foil printing also better withstands wear and abrasion issues compared to glitter inks.

The limitations are that precise alignment is essential for clean results. Due to the costs of foil materials and added production steps, it also tends to be one of the more expensive enhancements. For simple foil accents, most printers use a foil adhesive specifically formulated to bond the metallic layers.

Conclusion

Getting creative with different screen printing techniques opens up a wider range of design possibilities compared to standard spot color printing alone. The various methods each have their own strengths and applications.

• Spot colors – great opacity and durability. Best for simple graphics.
• Simulated process – mimics full-color look while using spot inks.
• Process colors – exceptional photorealism but more transparency on dark shirts.
• Discharge – removes dye for a faded effect.
• Water-based ink – softer feel, more eco-friendly.
• Foil printing – eye-catching metallic effects.

Combining multiple techniques allows maximizing the advantages while minimizing limitations. Soft hand water-based underprint with plastisol on top. Photorealistic process prints with spot color accents. Discharge effects and foil accents. The options are vast.

Work with your printer to select the best approach for achieving your creative vision within your budget and timeline needs. The right techniques can take your custom t-shirt designs to the next level.