Halftone generator
Turn a picture into halftone films for screen printing or DTF: dots at your LPI, angle and film DPI, one film per ink, saved as a 1-bit PNG or a true-size PDF. Runs on this device; the picture is never uploaded.
Open a picture to make its films.
Tap the picture to set ink 1.
What you are printing
Dots
Tones under the smallest dot print nothing; tones over the largest print solid.
Print size and film
Open a picture to see the film size.
The height follows the picture. Use your film printer's DPI (often 600 or 720) or a whole fraction of it.
Make and save
Small films update as you change settings; big ones wait for this button.
Privacy: nothing is uploaded. Your picture is turned into films inside this browser. Nothing is saved: close the tab and it is gone. The page sends an anonymous page-view count and two fixed event names (make, download), never the picture, its file name, its colours or its size.
How to make halftone films
- Open the picture. Tap Choose a picture, drop a file or paste one. A PNG with a transparent background is best for DTF.
- Say what you print. One ink turns the greys into dots of a single colour. Spot colours splits the picture into up to 4 inks: tap Find inks in the picture, or tap an ink's dropper and then the picture, or type its hex. Tick the white underbase for a dark shirt. DTF keeps the colours and turns soft transparency into dots.
- Set the dots. Choose the shape, the LPI for your mesh (the line under the slider gives the mesh range) and the smallest and largest dot your screens hold.
- Set the print width and film DPI. The film's pixel size and the PDF page size are shown underneath.
- Check and download. Look at the print preview on your shirt colour, then each film with Dots 1:1, and download each film as a PNG or a PDF. Print the PDF at 100 % (no "fit to page"); the registration marks line up from film to film.
What it cannot do
- No CMYK process separation and no colour profiles. Spot colours are split by matching each pixel to the nearest ink you name; it does not make simulated-process or four-colour process films, and it does not read ICC profiles.
- Screen colours are not ink colours. The preview mixes the inks on screen as light; real plastisol or water-based ink on fabric looks different, especially without an underbase. Pick the ink by its swatch, not by the screen.
- Large 1200-DPI films are slow on a phone. A 12-inch film at 1200 DPI is over 200 megapixels and is refused; up to 60 megapixels per film works, but on a phone each film can take a minute. Use 300 to 600 DPI there.
- No dot-gain curve. Dots spread on the shirt, mostly in the midtones; lighten the picture first if your prints come out dark. The smallest and largest dot settings are the only compensation here.
- No choke or spread. The underbase is the same size as the inks over it, not shrunk under them.
- It makes films, not screens. Mesh, emulsion, exposure and squeegee are still yours; test a step wedge before a big run.
Where the defaults come from
Smallest and largest dot. Anatol's guide How to Get Started Screen Printing with Halftones (fetched 2026-10-20): For screen printing, you should set haltones to at least 6 percent, as anything smaller becomes difficult to print accurately, and to no more than 97 percent. Many screen printers will cut the maximum percentile in the upper 80s, as dots that are any larger can merge to create a solid image due to dot gain.
So the defaults here are 6 % and 97 %; if your shadows fill in, set the largest dot to 85–89 %.
Mesh for an LPI. Screenprinting.com's help article What mesh count should I use for halftones? (fetched 2026-10-20): A good rule of thumb is to choose a mesh count that is 4–5 times your halftone line frequency (LPI).
The line under the LPI slider applies it: 45 LPI gives 180–225 mesh.
Angles. Screenprinting.com's crash course in halftones (fetched 2026-10-20): A good rule of thumb is to use 22.5° angles.
That is the one-ink default. For several inks, Thrive Screen Printing's halftone guide (fetched 2026-10-20) lists the set Y 7.5°, C 22.5°, K 52.5°, M 82.5°
, 30° apart; inks 1 to 4 here default to 22.5°, 52.5°, 82.5° and 7.5°. The underbase defaulting to ink 1's 22.5° is this tool's own choice, not from a source. Every angle can be changed.
How the dots are made
The film is a grid of cells, LPI cells per inch, turned by the screen angle. Each cell holds one dot whose area is the tone of the picture there: a 30 % grey gets a dot covering 30 % of its cell. At 300 DPI and 45 LPI a cell is 6.7 film pixels wide, so a dot can only grow in about 44 steps; at 600 DPI it is 13.3 pixels and about 178 steps, which is why fine LPIs want a fine film. The pixels of each cell are ranked by the dot shape (round dots grow from the centre and stay separate up to 78.5 %, where neighbours touch; after that the clear holes between them shrink) and a tone of t % prints the first t % of them. That keeps the ink share exact: a flat 50 % grey prints exactly half of every cell. Every film pixel is black (ink) or clear, and the PNG is a true 1-bit file with its DPI in the pHYs chunk (300 DPI = 11,811 pixels per metre), so it opens at its true size.
Questions
Is there a free online halftone generator for screen printing films?
Yes, this page. It makes the film itself, not just a halftone look: one bit per pixel at the DPI of your film printer, dots at the LPI and angle you set, one film per ink, as a PNG with the DPI written in or a true-size PDF with registration marks. It is free with no sign-up and no watermark, and the picture never leaves your device.
How do I halftone a design for DTF?
Choose DTF, open a PNG with a transparent background (or tick Make the background colour transparent for a picture on a plain background), set the print width and your printer's DPI, and download the PNG. Every pixel in it is either fully opaque or fully clear: soft shadows, glows and faded edges become dots, so the printer never lays down half-transparent ink that the white layer and powder show up as a grey haze.
What LPI and mesh count should I use for halftones?
A common rule is a mesh count 4 to 5 times the LPI, so 45 LPI wants roughly a 180 to 225 mesh and 55 LPI a 220 to 275 mesh. 45 LPI suits most halftone shirt prints; 55 to 65 LPI holds finer detail but needs a finer mesh and a sharp exposure. The tool shows the mesh range for the LPI you pick.
Can it make line halftones?
Yes. Pick the Line dot shape: the tone becomes parallel lines whose width follows the picture, LPI lines per inch, at the angle you set. Round, ellipse and square dots are the other shapes.
What DPI should a halftone film be?
Make it at your film printer's resolution, or a whole fraction of it, so the printer does not resample the dots. The finer the film, the more grey steps a dot can show: at 300 DPI a 50 LPI dot is 6 × 6 pixels, so 37 steps; at 600 DPI it is 12 × 12, so 145. 600 DPI is a good default for inkjet film; 300 DPI keeps files small on a phone.
Why does each ink get a different angle?
Two dot screens at the same angle, or a few degrees apart, interfere and print a moiré pattern of light and dark bands. Spacing inks 30° apart keeps that pattern too fine to see, so the defaults here are 22.5°, 52.5°, 82.5° and 7.5° for inks 1 to 4. A single ink defaults to 22.5°, which also keeps it off the mesh threads.