Screen printing works by pushing ink through a mesh screen that has a stencil on it, transferring a design onto fabric, paper, or other surfaces. The basic concept is simple, but the full process involves several precise steps: creating the stencil, choosing the right mesh and ink, pulling the print, curing it, and cleaning up for the next job. Here’s how each stage works.
Creating the Design and Film Positive
Every screen print starts with artwork separated into individual colors. Each color in the final design gets its own screen, so a four-color design requires four separate stencils. The artwork for each color is printed or drawn onto a transparent sheet called a film positive, where the design appears in solid black against the clear film. This can be done digitally with an inkjet printer, hand-drawn with opaque ink, or cut from a UV-blocking masking film.
Coating and Exposing the Screen
The screen itself is a frame stretched with fine mesh fabric. To turn it into a stencil, you coat it with a thin, even layer of light-sensitive emulsion using a scoop coater, then let it dry in a dark room. Once dry, you place the film positive flat against the coated screen and load it into an exposure unit that blasts ultraviolet light through the film.
Here’s where the chemistry matters. Wherever UV light hits the emulsion directly, it hardens and bonds permanently to the mesh. But wherever the black areas of your design block the light, the emulsion stays soft and water-soluble. After exposure, you spray the screen with water, and those soft, unexposed areas wash away cleanly, leaving open mesh in the exact shape of your design. The hardened emulsion surrounding it stays put, blocking ink from passing through everywhere except your image.
Getting the exposure time right is critical. Underexpose, and the background emulsion washes out along with your design. Overexpose, and the fine details of your image harden shut. The emulsion in exposed areas should look noticeably darker than the protected areas, which stay a lighter color until they’re washed away.
Choosing the Right Mesh Count
Not all screens are the same. The mesh count, measured in threads per inch, controls how much ink passes through and how much detail the screen can hold. Lower mesh counts have larger openings that let more ink through but capture less detail. Higher counts do the opposite.
- 60 to 90 mesh: Best for thick specialty inks like metallics, shimmer, and puff inks that need wide openings to pass through.
- 110 mesh: The standard for white plastisol ink on dark garments. The thick white ink needs room to flow.
- 160 mesh: The most popular all-around count, working well with many ink types and materials.
- 200 to 230 mesh: Used for high-detail artwork, fine lines, and small text. Also the go-to for water-based inks on wood or paper.
- 280 to 305 mesh: Reserved for extremely fine detail, halftone dots, and full-color process printing.
The material you’re printing on matters too. Fleece soaks up ink, so printers typically drop to a 110 or 160 mesh for better coverage. Paper needs at least a 200 mesh to prevent bleeding. The decision always comes down to balancing ink thickness, design detail, and substrate absorbency.
Setting Up the Press
With the stencil ready, you lock the screen into a press, which holds it on hinges above a flat printing surface called a platen. The screen doesn’t sit directly on the garment or paper. There’s a small gap between the mesh and the surface called “off-contact distance,” typically between 1/32 and 1/16 of an inch for t-shirt printing. This gap ensures the mesh snaps cleanly away from the surface after the squeegee passes, preventing smearing. For water-based inks on t-shirts, placing a dime on each corner of the platen gives you roughly the right spacing.
Pulling the Print
Printing itself happens in two strokes. First, you lay a thick bead of ink along the top of the screen and pull it across the stencil with a squeegee to “flood” the mesh, filling all the open areas with ink. Then you place your garment or paper on the platen, lower the screen, and push the squeegee firmly back across in the opposite direction. This second pass forces ink through the open mesh and onto the surface below.
The squeegee is more important than it might seem. Squeegees come in different hardness ratings measured in durometer. A 70-durometer blade is the industry standard for general printing, offering a good balance of flexibility and firmness. Softer blades (around 60 durometer) bend more and deposit heavier layers of ink, making them ideal for raised puff prints. Harder blades (80 durometer) lay down thinner, more precise ink films for fine detail work on smooth surfaces.
Angle matters too. Holding the squeegee closer to 45 degrees pushes more ink through, while a more upright angle deposits less ink and produces sharper detail. Most printers start at 70 durometer and a moderate angle, then adjust based on results.
Printing Multiple Colors
Single-color prints are straightforward, but most designs use several colors, and each one requires its own screen and its own pass through the press. The challenge is making sure every color lands in exactly the right position relative to the others. Even a fraction of a millimeter off, and colors overlap or leave visible gaps.
Printers solve this with registration marks: small target symbols placed in consistent locations (usually the corners) on every screen in the set. You align the first screen’s marks with reference points on the press, lock it down, and print the first color. Then you swap in the next screen, line up its registration marks to match the same reference points, and print the second color on top. This repeats for every color in the design. On a manual press, this is done by eye and by hand. Automatic rotary presses use mechanical systems to hold registration more consistently across hundreds of prints.
Curing the Ink
A printed garment isn’t finished until the ink is fully cured. For plastisol ink, the most common type in garment printing, the ink doesn’t air-dry at all. It needs heat to fuse. When plastisol is heated, its resin particles absorb the surrounding liquid and swell until they merge into a tough, flexible film that bonds to the fabric.
Most plastisol inks reach full cure at around 320°F (160°C). Below about 250°F, the ink may feel dry to the touch but is only partially gelled, and it will crack or wash off. Printers run garments through a conveyor dryer or use a flash cure unit held about 3 inches above the print for 25 to 35 seconds. One important consideration: plastisol is a thermoplastic, meaning it will re-soften if exposed to high heat after curing, which is why printed garments shouldn’t be ironed directly on the design.
Water-based inks cure differently. They dry through evaporation as the water in the ink escapes, then typically need a heat set to lock in durability. The result is a softer feel, since the ink soaks into the fabric fibers rather than sitting on top. This “soft hand” is why water-based printing is popular for premium t-shirts and towels where the print should feel like part of the fabric rather than a layer on it.
Plastisol vs. Water-Based Ink
Plastisol is the default for most garment shops because it’s forgiving. It never dries in the screen, so you can leave it sitting during a break without clogging the mesh. It comes ready to use straight from the container, rarely needs additives, and leftover ink goes back in the bucket for next time. It prints well on both light and dark fabrics and can be layered wet-on-wet without waiting for each color to dry, which speeds up production significantly.
Water-based ink is trickier to work with. It dries in the screen if you pause too long, requires finer mesh counts to prevent bleeding (since it’s much thinner than plastisol), and needs more sophisticated drying equipment. But the payoff is a print that’s nearly invisible to the touch. Water-based inks are also the standard for high-speed roll-to-roll printing on fabric yardage, where ink penetration into the material is the whole point.
Reclaiming Screens for Reuse
Screens are expensive, so printers reclaim and reuse them. The process strips away both the ink and the emulsion, returning the mesh to a blank state. It takes five steps.
First, you scrape excess ink off with a spatula and clean the remaining ink from the mesh using a screen wash solvent and a soft nylon brush, followed by a low-pressure rinse. Next, you apply a stencil remover (essentially an emulsion-dissolving chemical) to both sides of the screen. You either scrub it immediately with a brush or let it soak for 30 to 60 seconds. Never let the remover dry on the mesh, or it can create its own residue problem. After scrubbing, a pressure washer blasts away any stubborn emulsion or ink remnants.
The final step is degreasing. A small amount of degreaser scrubbed into both sides of the clean mesh removes oils, dust, and chemical residue that could cause the next coat of emulsion to adhere unevenly. A clean, degreased screen coats smoothly and exposes predictably, which is why experienced printers treat this step as non-negotiable rather than optional.