Definition
Halftone printing is a technique that recreates smooth gradients, shading and photographs using a pattern of tiny dots that vary in size or spacing. From a normal viewing distance your eye blends the dots into continuous tone, so a design that only uses one or two solid inks can look like it fades and shades. It is the reason a single ink can print a photo-like image on a t-shirt.
Definition
Halftone printing turns a continuous-tone image, like a photo or an airbrushed illustration, into a grid of dots. Where the image is dark the dots grow large and touch, where it is light they shrink to specks or disappear. The printer lays down one solid ink, but the changing dot size fools the eye into seeing a full range of tones. For example, a grayscale portrait can be screen printed with one black ink: the shadows read as dense clusters of dots and the highlights as sparse ones, giving the illusion of soft shading without mixing a single gray.
How halftone printing works
Halftone printing starts by converting artwork into a dot pattern at a set frequency, measured in lines per inch (LPI). A low LPI means large, visible dots and a coarse look. A high LPI means fine dots and a smoother result. Garment printing uses far coarser halftones than paper, often 35 to 65 LPI, because fabric texture and ink spread cannot hold the fine detail that glossy paper can.
Each dot also sits at a screen angle. When you print more than one color, the screens are rotated to different angles so their dots interlock into a small flower-like rosette instead of clashing. Get the angles wrong and the overlapping grids fight each other, creating a distracting wavy pattern called moiré. This is the same principle behind CMYK process printing, where four halftone screens combine to build full color.
The main trade-off is dot gain. Ink spreads as it is pushed through a screen and pressed into fabric, so a 40 percent dot on screen can print closer to 55 percent on a shirt. Good separators pull very small highlight dots and very large shadow dots that would fill in, keeping the tonal range printable. Balanced against that, halftones let you reproduce complex imagery with fewer inks and fewer screens, which keeps setup simple and cost down.
Halftone printing in branded merch
- Photo-real prints with fewer screens. Reproduce a detailed illustration or photograph using simulated process or four-color process printing, keeping the ink and screen count low so a rich image stays affordable at volume.
- Gradients and fades from one ink. Create an ombre effect, a soft shadow or a logo that fades out using a single ink color, adding depth without paying for extra colors.
- Vintage and distressed textures. Use coarse, visible halftone dots to give apparel a retro, worn-in look that reads as intentional design rather than a flaw.
Halftone printing simulates continuous tones and gradients by breaking an image into dots of varying size or density that the eye blends into smooth shading.
5 tips to elevate your Halftone printing strategy
| Tip | Steps |
|---|---|
| Match LPI to the fabric | Use a coarser halftone, around 45 to 55 LPI, for garment screen printing so the dots hold on textured fabric. |
| Set correct screen angles | Angle each color screen apart, commonly 22.5 degrees, to prevent moiré where dots overlap. |
| Plan for dot gain | Avoid dots under about 10 percent or over 90 percent, since they drop out or fill in during printing. |
| Choose the right mesh | Pair fine halftones with a higher mesh count so the screen can resolve small dots cleanly. |
| Test on the final color | Print a proof on the actual garment color, using an underbase on dark fabric to keep tones accurate. |
Key Terminologies
Frequently Asked Questions
What is halftone printing used for?
It is used to reproduce gradients, shading and photographs with a limited number of solid inks. In merch it lets screen printers create photo-like images and soft fades on t-shirts and hoodies without mixing every tone.
What is the difference between halftone and CMYK?
Halftone is the dot technique itself. CMYK is a specific use of it, layering four halftone screens of cyan, magenta, yellow and black to build full color. All CMYK printing is halftone, but a halftone can also use a single ink.
Can you print halftones on t-shirts?
Yes. Screen printing and DTG both reproduce halftones on fabric. Screen printing uses coarser dots because ink spread and fabric texture cannot hold fine detail, so garment halftones look bolder than those on paper.
What LPI is best for halftone screen printing?
Most garment work sits between 35 and 65 LPI, with 45 to 55 LPI a safe middle ground. Lower LPI is more forgiving on rough fabric, while higher LPI needs fine mesh and careful control to avoid dots filling in.
What causes moiré in halftone printing?
Moiré appears when two or more halftone screens overlap at similar angles, so their grids interfere and create a wavy pattern. Setting each color screen at a distinct angle keeps the dots interlocking cleanly instead.