Understanding Halftones in Apparel Printing
By The Velocity Wear Team
A halftone is continuous tone reproduced as a grid of dots of varying size. Screen printing can only lay ink down or leave it off, so a smooth gradient is simulated by shrinking and growing dots until, at normal viewing distance, your eye blends them into shades. Finer halftones use smaller dots, and smaller dots need a higher mesh count to hold them cleanly.
Why the Dots Exist at All
A screen is a stencil. Ink either passes through an open area or it does not. There is no dial for fifty percent ink. So a mid grey is printed as dots covering roughly half the area, a light grey as dots that have shrunk, a dark grey as dots that have grown until they nearly touch. The dots sit on a fixed grid at a fixed frequency, usually described in lines per inch, and only their size changes. Print them small enough and your eye stops resolving individual dots and reads an average instead.
Fabric Is a Difficult Place to Put a Small Dot
Paper is smooth, flat and dimensionally stable. A knitted jersey is none of those. Ink pushed through a screen spreads into the yarn, so every dot lands larger than it was drawn. That spread is called dot gain, and it means a design that looks correctly balanced on a monitor prints darker and heavier than expected, with the midtones filling in first.
Then there is the surface itself. On coarse, textured or brushed fabric the cloth has hills and valleys of its own, and very small dots land in the wrong place or fail to make contact at all. Below a certain size on a textured garment, a halftone stops behaving like a tone and starts behaving like noise.
The Detail Where Most Gradients Fail
This is worth knowing before you design anything with a fade in it. A gradient that ramps all the way down to zero will not disappear smoothly on fabric. Below a certain dot size the dots stop transferring reliably, so instead of a soft vanish you get a ragged, speckled tail that reads as a printing fault. The fix is a design decision, not a production one. End the fade at a low but solid percentage and stop it deliberately, or run it out behind a hard edge. A gradient with an intentional ending always looks better than one that dissolves into gravel.
- Dark garments: halftones over a white underbase mean two dot layers that must align, which tightens tolerances considerably.
- Coarse mesh: a mesh too open cannot support the smallest dots and they wash out of the stencil.
- Textured fabric: brushed fleece, heavy canvas and slub jersey all break up fine dots.
- Very fine line counts: pushing the frequency up looks better in theory and is much less forgiving in practice.
- Large flat gradients: broad, gentle ramps show banding and dot gain far more obviously than small detailed areas.
Moiré, and Why It Appears From Nowhere
When the halftone grid and the fabric's weave sit at similar frequencies and angles, they interfere and produce a rippling pattern that existed in neither of them. It is the same effect that makes a striped shirt strobe on video. Rotating the halftone angle usually cures it. It is worth recognising mainly so you read it as physics rather than assuming someone printed the wrong file.
Simulated Process Versus Four-Colour Process
Two different uses of halftones get confused. Four-colour process splits artwork into cyan, magenta, yellow and black, and works best on white or very light garments, because those inks are translucent and rely on the substrate underneath to supply brightness. Simulated process uses a set of opaque spot colours, each of them halftoned, printed over a white underbase. It is more screens and more setup, and it is what makes photographic work possible on a black hoodie at all.
Digital Methods Handle Tone Differently
DTF and DTG also break tone into dots, but they place tiny droplets at high resolution rather than forcing ink through a stencil, so gradients and photographic detail are far easier. If your design is genuinely photographic and the run is short, that is usually the more sensible route. Screen printing earns its place when the quantity is high enough for the per-colour setup to pay for itself.
“"Screen printing cannot print grey. It can only print black in smaller and smaller pieces, and trust your eye to finish the job."”
What to Send, and What to Ask
Send the artwork at full size and full resolution with the tones intact. Do not pre-convert your own halftones unless you have been given a line count and angle to work to, because a halftone applied twice produces exactly the interference pattern described above. Say where the design will be seen from, too. Merchandise examined at arm's length and a back print viewed across a room have very different requirements, and the second one is much easier to satisfy.
You can position the design and preview the layout in the free Design Studio, and the instant price calculator shows how colour count and quantity move the numbers, since every screen colour carries its own setup. Minimum order is 20 pieces with sizes mixed freely within the run, and bulk discounts reach up to around 40% as quantities rise.