How to make a halftone portrait

What a halftone is#

Printing presses cannot print grey. They print ink or no ink. A halftone fakes grey by printing dots of varying size on a regular grid: from a distance the eye averages a big dot and its white surround into a dark grey, a small dot into a light grey. Newspapers, comics and screen prints all work this way, which is why the look reads as printed even on a screen. The pop-art portrait is a halftone made coarse enough that the trick is visible.

Three things decide how a halftone looks: the spacing of the grid (dot size), how quickly dots grow with darkness (contrast), and the photo underneath. Most disappointing halftones have the third problem, not the first two.

Choose and prepare the photo#

• Strong light and shadow. A face lit from one side, with real shadows, gives the dots something to describe. Flat, even lighting turns into a uniform grey field of medium dots.
• A plain background. Busy backgrounds become busy dots and compete with the face. Remove or darken it first (Remove a background does it on your device).
• Crop tight. Halftone reads at a distance; a small face in a big frame becomes a smudge.
• Black and white, then contrast. Convert to black and white and push the contrast so the brightest skin goes almost white and the darkest shadows almost black. In the Editor, a Curves or Levels adjustment layer does this without touching the photo (Adjustment layers).

Dot size: match it to where it will be seen#

Dot size is really grid spacing, and the right spacing depends on the output size, not on how it looks zoomed out on screen. In Voidcanvas the Dot Size slider runs from 10 to 100 and sets a cell of roughly Dot Size ÷ 8 pixels on the working image (so 40 gives a 5 px cell, 80 a 10 px cell). When you download from the Halftone tool at full size, the setting is scaled with the image so the result matches the preview.

Contrast: fill the shadows, keep the face#

Contrast (20 to 100) controls how large dots grow for a given darkness. At 50 the darkest dots just fill their cell. Above 50, dark dots grow into each other and shadows become solid black, which is the punchy comic look. Below 50, every dot shrinks and the whole image lightens. For a portrait, raise it until the shadow side of the face goes solid but the eyes and the bridge of the nose still read as separate dots. If the eyes vanish, back off, or paint the effect out of the eyes afterwards (below).

Colour the dots#

The effect produces black dots on white. Colour is added afterwards with a layer and a blend mode, which is also how it was done on paper: ink colour and paper colour.

• Coloured dots on white: put a solid colour layer above the halftone and set it to Screen. White stays white; the black dots take the colour.
• Black dots on coloured paper: put the colour layer above and set it to Multiply. The white becomes the colour; the dots stay black.
• Coloured dots on coloured paper: do both, with two colour layers, or use a Duotone filter under the halftone to tint the photo first, then set the halftone layer itself to Multiply so its dots print over the tint.

Blend modes are explained in Blend modes and opacity.

Variations#

• Two-tone poster: Duotone first (a deep colour for shadows, a pale one for highlights), then Halftone at a coarse setting on Multiply.
• Cut-out portrait: remove the background, halftone the person only, and put them on a flat colour.
• Sharp eyes: apply the halftone as a filter layer in the Editor, then erase it over the eyes so they stay photographic. The contrast between dots and detail is the whole trick.
• Random dots instead of a grid: the Stipple effect scatters dots by density rather than on a grid. Dither gives a fine, non-grid pattern that suits small sizes.
• Light dots on dark: Dot Matrix keeps colour and puts bright dots on black, the reverse of a halftone.

How to do it in Voidcanvas#

Quickest: the Halftone tool

1. 1Open the Halftone tool. A sample is loaded so you can see the effect before you do anything.
2. 2Click Upload your image or drop your photo on the preview. Nothing is uploaded anywhere; the page does the work in your browser.
3. 3Set Dot size and Contrast under Adjust, using the table above for the size.
4. 4Press Download PNG. The file is rendered again from your original at its own size (up to 8000 px on the long edge) with the settings scaled to match the preview, and named halftone-<width>x<height>.png.
5. 5Or press Send to Layer Stack to open the Editor with your photo as one layer and the halftone as a live filter layer above it, ready to recolour and mask.

In the Editor, as an editable layer

1. 1Open the photo and prepare it: crop, then add a Black and white and a Curves adjustment layer from the Layers panel's New adjustment layer menu.
2. 2Choose Filter, Filter gallery… and click Halftone. It is added as a layer named Halftone filter above everything below it.
3. 3Select the filter layer and set Dot Size and Contrast in the Filter settings section of Properties.
4. 4To keep the eyes sharp, pick the Eraser with the filter layer selected and paint over the eyes. The Editor adds a mask for you; paint with the Brush to bring the effect back.
5. 5Add a colour layer above: Layer, New layer, then Edit, Fill… (Shift+F5) with your colour, or draw a rectangle over the whole canvas. Set its blend mode to Screen or Multiply as described above.
6. 6Export as PNG (Ctrl+E). PNG keeps the dots crisp; JPG softens them.

Common mistakes#

• Grey soup. The photo had no contrast. Fix the photo first; no slider rescues flat lighting.
• Dots too fine for print. They fill in on paper and the portrait goes dark. Use the table and think in millimetres.
• Moiré (wavy interference patterns). The halftone was scaled after it was made, or a second grid was laid over it. Make it at final size, once.
• Soft dots. Exported as JPG, or scaled up. Export PNG at the size you made it.
• Eyes gone. Contrast too high with no mask. Lower it or erase the effect over the eyes.

Open the Halftone tool