A sample picture is already turned into dots. Choose a picture of your own, or make a fade or a flat tint with no picture at all, pick the dot, the screen and the angle, and download an SVG in which every dot is a real shape.

Free, no account. The file is read by code running in your browser. It is not uploaded, and nothing about it is stored.

How to make a halftone

Look at the sample the page opens with: a shaded ball, drawn as round dots on a grid turned 45°.
Press “Choose your own picture” and pick a PNG, a JPG or a WebP. Or press “A fade” or “A flat tint” for a pattern that needs no picture.
Pick the dot (round, square, lines or diamond), the screen (coarse, medium or fine), the angle and whether it is black on white or white on black. The picture changes with each press.
Open Fine-tune for the exact cell size in millimetres, the largest dot, the size of the page and the ink colour.
Download the SVG. “Download PNG” gives the same picture as pixels.

What a halftone is, and what this one does

A halftone shows greys with one ink. The page is divided into a grid of equal cells, and each cell gets one mark whose size carries the tone: a large dot where the picture is dark, a small one where it is light, none where it is white. From a little distance the eye blends ink and paper into grey. The guide What is a halftone? tells the longer story.

This free halftone generator works that out exactly. For every cell it takes the mean darkness of the picture under it, and draws a mark whose area is that share of the cell: under a patch that is 30% dark, the dot covers 30% of its cell, so 30% of the paper there is inked. A cell lighter than half a percent gets no dot, which keeps speckle out of white paper. Colours are read as brightness, weighing red, green and blue as television does (0.299, 0.587 and 0.114), and see-through parts of a picture count as white.

That is different from the site’s photo editor, whose Dither style places dots of one size closer together or further apart. Here the dots keep their places and change size, which is what the word halftone means in printing.

The four dot shapes

Round. A true circle, written as two arcs. A circle touches its neighbours when it is as wide as its cell, and by then it covers 78.5% of the cell (π ÷ 4). For darker tones the dot is the part of a larger circle that lies inside its own cell: a circle with four flat sides, and at 100% the whole square. In an even tone that is exactly the shape overlapping circles merge into, with a small pinched patch of paper left at each corner.
Square. A square in line with the grid. It never touches its neighbours until the cell is solid.
Lines. One line to each row of cells, as wide at the middle of each cell as the tone there asks, and straight from one middle to the next, so a line swells and thins along its length. A line breaks where the picture is white.
Diamond. A square stood on its corner. Its corners reach the edges of the cell at 50%, which makes a chessboard; darker than that the corners are cut off flat against the cell, so the dot becomes eight-sided and then square.

Screen, angle and size

The screen is the size of one cell. Coarse is 4 mm, medium 2 mm and fine 1 mm, so on the 200 mm page the tool starts with, a medium screen has 100 cells across. Printers count a screen in lines to the inch, which is 25.4 divided by the cell in millimetres: 6.35, 12.7 and 25.4 for the three named screens. Those are poster and pop-art sizes, with dots you are meant to see. For a screen meant to disappear, type the cell under Fine-tune: 45 lines to the inch is a cell of 0.56 mm.

The angle turns the whole grid anticlockwise. 45° is the classic choice for one ink, because rows of dots are least noticeable on the diagonal. A square grid turned 90° lies on itself again, so the angles from 0° to 90° are all there are; 15° and 75° are mirror images of each other. With lines, the angle is the way the lines run: level at 0°.

The page is in millimetres, 200 wide unless you change it, and a picture’s height follows its proportions. A dot is drawn only where its whole cell lies on the page, so every dot in the file is whole and the edge of a turned grid is slightly ragged. One file holds at most 120,000 marks. At 45 lines to the inch that is about 380 square centimetres, roughly six tenths of an A4 sheet; for a larger print, use a coarser screen or make the picture in parts.

What is in the SVG

One <path> holds every mark, each as its own closed outline: this is a compound path. It is written that way, and not as thousands of separate circles, for three reasons. A drawing program opens it as one object that takes one colour, where separate circles would be thousands of things to select. Marks that meet along an edge are parts of the same filled shape. And white on black has to be a single shape, because its dots are holes in it. A compound path can still be split into its pieces (Break Apart in Inkscape, Release Compound Path in Illustrator) if you want the dots one by one. Circles stay true circles, as arcs, and are not approximated with curves.

No two marks overlap. With the largest dot at 100% of the cell, marks in the darkest parts meet their neighbours along the edges of their cells, and the page counts how many. Set the largest dot lower, say 90%, and no mark is ever wider than that share of its cell: a gap is kept between every pair, and tones too dark for the largest dot are capped at it. The page says how many cells were capped and at what tone.

White on black is one black shape the size of the page with the dots as holes in it, not white dots laid over a black rectangle. On white paper the two look the same, but the holes are real: a cutter or a laser gets a sheet with openings.

The size is exact. The width, height and viewBox are in millimetres, and positions are written to a thousandth of a millimetre.

What it is for, and what it is not

A one-ink halftone is the way to put a photograph or a shaded drawing where only ink or no ink is possible: a film positive for a screen-printing stencil, a laser engraving, a rubber stamp, a risograph or photocopied zine. It is also simply a look: comic-book shading, pop-art portraits, a fading band of dots behind a heading. A fade or a flat tint made here is a pattern to lay under other artwork.

It is one ink, one grid. This page does not make CMYK separations, where a colour picture is split into four halftones at four angles; the guide to CMYK halftone explains those. It does not allow for dot gain, the way wet ink spreads on paper or fabric and prints every dot a little larger, and it has no elliptical dot. For screen printing, read halftones for screen printing for the rulings and mesh counts that hold a dot, and test a strip before you burn a full screen.

A very large picture is scaled down to 1,600 pixels on its longer side before the dots are sized, and the page says when it has done so. At the finest screen the page will draw, a picture in the usual 4 to 3 shape still has four pixels across each cell. The PNG is drawn at 300 pixels to the inch of the page, 2,362 pixels wide for 200 mm, up to 6,000 pixels on the longer side, and is see-through wherever there is no ink.

Questions

Does it make colour or CMYK halftones?

No. It makes one halftone in one ink colour, which you can change under Fine-tune. A colour picture is read as greys. Four-colour separation, with a screen for each of cyan, magenta, yellow and black at its own angle, is a different job that this page does not do.

Can I cut or engrave the dots?

Yes: every dot is a closed outline, which is what the guide to vector halftones means by the term. For cutting, set the largest dot to 90% or less so that no two dots share an edge, use a coarse screen, and remember that each dot is a separate piece to weed or a separate hole. For engraving, use the SVG where your laser program fills vector shapes and the PNG where it wants pixels; with the PNG, switch off the program’s own dithering, because the picture is dots already.

How do I match a screen ruling in lines per inch?

Divide 25.4 by the ruling and type the answer as the cell size under Fine-tune. 30 lines to the inch is 0.85 mm, 45 is 0.56 mm and 55 is 0.46 mm. The page shows the ruling for whatever cell you set.

Why are the dots in the dark parts not round?

A round dot as wide as its cell covers only 78.5% of it. To show a darker tone truly, the dot has to take up more of the cell, so its sides flatten against the cell’s edges and it joins its neighbours, as the dots of a printed halftone do in shadows. If you would sooner keep every dot round, lower the largest dot under Fine-tune; the darkest tones are then drawn lighter than they are, and the page tells you how many cells that touched.

What kind of picture works best?

One with a clear subject and a full range of tones, from white to nearly black. Fine detail smaller than a cell is averaged away, so a face that fills the frame works where a crowd does not. If the result is too heavy or too pale, move “Middle tones” under Fine-tune, which lightens or darkens the greys and leaves black and white where they are.

Halftone generator