Image Posterizer & Colour Separator
Reduce a photo to a few flat colours, then get one printable layer per colour with its hex code and coverage. Built for screen printing, stencils, and riso-style posters.
Drag and drop an image here, or
k-means minimises the average colour error and suits photos; median cut keeps hard-edged blocks and suits flat graphics.
Inks in the separation
Upload an image to choose which inks to keep.
Combined preview
About this tool
This posterizer and colour separator runs entirely in your browser. Your image is reduced to the number of flat colours you choose — with k-means clustering or median-cut quantisation — and every pixel is then assigned to one of those inks, so the coverage percentages add up to 100%.
Each separation downloads as a transparent PNG of a single ink, and the ZIP holds every layer plus a README with the hex codes and coverage, ready to turn into screens or stencils. Large images are sampled down to 1000px on the long side for speed, and nothing is ever uploaded.
- 100% free — no account needed
- Runs in your browser
- Nothing is uploaded
Frequently asked questions
Is Image Posterizer & Colour Separator really free?
Yes. Image Posterizer & Colour Separator is completely free on PureBrowser — every feature, with no account, no trial, and no credit card.
Does Image Posterizer & Colour Separator upload my data?
No. Image Posterizer & Colour Separator runs entirely inside your browser, so anything you type, paste, or open stays on your own device.
Do I need to sign up or install anything?
Neither. There is no account and nothing to download — open the page and Image Posterizer & Colour Separator is ready to use on desktop or mobile.
Does Image Posterizer & Colour Separator work offline?
Once the page has loaded, yes. All of the processing happens locally in your browser, so it keeps working without a connection.
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