Screen Printing: Process + Techniques

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January 28, 2021

As you may have heard by now, hybrid printing is rising in popularity. New screen-printing chemistry is available; decoration on more specialty products is being attempted and achieved; and more new users are adopting this technology into their workflows. The large group of new hybrid users is allowing for more creative collaboration and, ultimately, decorators are seeing the advantages.

Hybrid printing involves adding CMYK digital print heads as a station to an automatic screen-printing press. While neither screen printing nor digital direct-to-garment (DTG) decorating are new, the combination of the two in a single production application is gaining popularity among printers and apparel consumers.

Essentially, hybrid printing has three steps. First, you screen print an underbase. Next, print a “tie coat” or a “catching layer,” which is formulated to hold the pigment that will be sprayed on top. Digital inks work best when they are applied to a flat, smooth surface. Some newer screen-printing ink technologies only require the tie coat.

The next step is using the digital unit to print the color that creates the design. The final step is to print a topcoat or binder. As the word implies, it seals in the pigment so that it will hold up during laundering. Some ink manufacturers put a binder in the ink used for the tie coat, which eliminates the need for a topcoat.

Finally, it’s important to note that hybrid printing isn’t DTG printing. The latter process requires pretreatment to fuse the digital inks to the garment’s surface, or to cause a digital white ink to gel and fuse. Hybrid printing is digital color applied to screen printing, and it doesn’t require pretreatment or fusing. I like to think of it as a giant coloring book. In the future, it may be possible to combine screen and DTG printing, bringing all three technologies together.

Ink & Setup
Hybrid screen-printing inks include all ink chemistries, with high-solids water-based ink being the most common type used. Plastisol inks also are compatible with hybrid printing, as are discharge inks. In fact, some ink manufacturers offer specially formulated digital discharge inks that perform optimally with the process. Hybrid printing also works well with special-effects inks, regardless of whether they are printed underneath or on top of digital inks.

One of hybrid printing’s greatest advantages is setup. With reduced screen counts and essentially the same rotations as screen printing, users can dial in setup times for maximum output on small to mid-size runs. Using the same output template for computer-to-screen (CTS) and hybrid units will align the screen with the hybrid quickly.

Micro movements are available on both screen and digital printers for any final tweaks. Ultimately, looking at the screen-printing process and ensuring standard operating procedures are in place and being followed will quickly dial in your hybrid process, enabling full jobs to be set up in less than five minutes every time.

Adding screens allows the user to control the print’s look and feel. For example, adding black-ink screens can result in a saturated black that a CMYK black can’t achieve. It also will maintain a traditional retail garment’s look and feel.

Special Effects
Depending on the type of topcoat used, you can achieve special effects with hybrid printing. The digital hybrid process loves special effects, so let’s say you want a shiny look instead of a matte look for a print. You can use a special-effects ink, such as a glitter, to create a sparkling look.

When screen printing a full-color, simulated-process image with a special effect, challenges exist in the number of colors required to make the print combined with the special effects and the amount of variations that can be produced in one setup. Using the hybrid process, a typical total of 14 simulated-process screens, plus special effect, can be reduced to two to four screens plus special effect. Variations can be output on each shirt during the single-setup print run, and new customer expectations can be established.

For example, you have a customer who brings in a yearly order for a restaurant: 300 short-sleeve tees in one garment color. If it’s a somewhat seasonal restaurant — beach-themed, for example — it probably has a slow season. This presents an opportunity to create a variation-themed tee.

For example, you could print a holiday tee for the winter months or a “Pinktober” tee for fundraising. By giving customers access to the variation, they can promote their businesses via social media or other outlets during those slower times. As a printer, you also can add 10-20 pieces of each variation onto the order with different garment colors, and perhaps upsell new products, like hoodies or sweat shirts.

The Color Factor
Color management in the digital space also is an important topic. First, you must understand that CMYK colors can be separated like traditional simulated process. The ideal CMYK separations contain “clean colors,” or what essentially is a more intense version of actual four-color process, leaving the value to be supported by the underbase on dark shirts. This means using underbase halftone whites, then adding cyan, magenta, yellow and sometimes black on top to colorize the print underneath.

I like to call this 3-D, four-color process. Ultimately, it involves removing value colors (like cyan) from the process separation and minimizing black. This creates the widest color gamut for the hybrid application.

In terms of Pantone Matching System (PMS) color, the same methods can be used. Finding the purest build of CMYK ultimately will yield the best results for the color gamut. There are powerful tools in RIP applications and design software, such as Adobe Photoshop, that help manage this output.

In hybrid printing, there are many variables. Just like with screen printing, the application’s color management requires some dialing in, and not every color is achievable using CMYK alone. Again, the advantage of a hybrid system is the ability to add screens, achieving any color on any fabric. Changes are faster in the digital space than via analog methods, so adjusting and testing for colors with hybrid printing can proceed quickly once standard procedures are established.

Hybrid printing has come a long way since its relatively recent inception and continues to evolve. This technology is here to stay and offers users many advantages that are worth exploring. The future of apparel printing will be modular, and the hybrid space is our first example of this. We will be able to build printing systems that allow decorators to choose how they want to achieve final results, allowing for the most versatility for the printer and the product. Hybrid printing provides a window into that future today.

Michelle Moxley is a career research, development and innovation expert with a demonstrated history of working in the apparel and fashion industries. She is skilled in screen and special-effects printing, separations, graphics, pre-press, digital printing and textiles. She currently is director of innovation at M&R Cos. For more information or to comment on this article, email Michelle at michelle.moxley@mrprint.com.