Image Halftone

What is the halftone effect?

Halftone is a printing technique that simulates continuous shades of gray using a grid of dots. Where the original image is dark, the dots are large and may merge together; where it is light, the dots are tiny or absent. Viewed from a normal distance, the eye blends the dots into smooth gradients, but up close the picture reveals itself as a field of variably-sized circles on a white background. The technique was invented for newspaper and magazine printing, where presses could only lay down solid ink, and it remains a familiar visual shorthand for "printed" or "vintage" imagery.

This tool reproduces that look entirely inside your browser. You upload an image, choose a dot size with the slider, and the tool reads the raw pixel buffer through the Canvas API. It then divides the picture into a grid of cells, computes the average brightness of each cell, and draws a black circle whose radius is proportional to the darkness of that cell. Nothing is uploaded, and the result is ready almost instantly.

How the halftone filter works

Under the hood the tool uses the Canvas 2D API. The source image is drawn onto an offscreen canvas, then getImageData returns the raw pixel buffer. The canvas is cleared to white, and the algorithm walks the image in steps of dotSize pixels. For each cell it averages the luminance of every pixel inside using the standard 0.299·R + 0.587·G + 0.114·B weighting, then draws a filled black circle at the centre of the cell. The circle's radius equals half the dot size multiplied by 1 − luminance / 255, so dark cells produce large dots that fill almost the entire cell, while bright cells produce tiny or invisible dots.

The dot size slider controls both the grid resolution and the maximum dot diameter. A small value (2–4 px) produces a fine, high-resolution screen that keeps fine detail; a large value (12–20 px) creates a coarse, graphic pattern with a strong retro or comic-book feel. Because the algorithm is a simple nested loop over the cells, even large images are processed in a fraction of a second.

Halftone vs other dot and pixel effects

Halftone is often confused with related effects, but the differences matter. Pixelate averages each block of pixels into a single solid square of colour, producing a mosaic without any circular shape. Dither scatters individual black and white pixels using error diffusion, trading dot patterns for fine noise. Posterize reduces the number of colour levels but keeps smooth shapes. Halftone, by contrast, always uses round dots on a white grid, and it is the only one of these effects that directly evokes the look of ink on paper.

The signature of a true halftone is the relationship between dot size and brightness — bigger dots mean darker tones. This makes halftone the right choice when you want a printed, engraved, or comic-strip appearance, rather than a digital mosaic or a noisy texture.

When to use a halftone effect

Halftone is a versatile stylistic choice that works across many design and creative contexts. Common scenarios include:

• Print and poster design. Give digital artwork the texture of screen printing or newsprint without needing a physical press.
• Retro and vintage looks. Recreate the look of 1950s comics, old newspapers, or pulp magazines in a single click.
• Backgrounds and textures. Use a halftoned photo as a subtle dotted backdrop that adds depth without distracting from foreground text.
• Logos and branding. A halftoned portrait or product shot can become a striking, graphic brand element.
• T-shirt and merchandise art. Halftone patterns survive screen-printing and embroidery better than fine gradients, making them ideal for apparel.

Whenever you want an image to feel printed, tactile, or graphically bold, halftone is the fastest route there.

How to apply a halftone effect to an image

Halftoning an image takes only a few seconds and everything happens locally in your browser — no upload, no sign-up, no watermark. Follow these steps:

1. Upload your image. Click the upload area or drag a JPG, PNG, WebP, GIF or BMP file into it. The image is decoded and previewed immediately.
2. Set the dot size. Use the 2 to 20 px slider. Smaller values keep fine detail; larger values create a bolder, more graphic pattern.
3. Choose an output format. Pick PNG for lossless quality, JPG for smaller photo files, or WebP for a balance of size and quality.
4. Click "Apply Halftone". The tool processes the image and shows the original and resulting file sizes side by side.
5. Download the result. Click "Download Halftone Image" to save the file. Your original is never modified.

Because every step runs locally through JavaScript, your images are never sent to a server. This makes the tool completely private, fast, and suitable for sensitive material.