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ToolSuite
Image Tools

Threshold an Image

Split an image into black and white at an exact brightness level.

or drag it here

image/* · up to 40 MB

128
Processed in your browser

Fill in the form and press “Process image” to see the result here.

How to use it

  1. 1Select your image, or drag and drop it onto the upload area.
  2. 2Adjust the options if you need something other than the defaults.
  3. 3Press the button. The image is processed on your device - nothing is uploaded.
  4. 4Download the result, or drop in another file to do it again.

About the Threshold an Image

Thresholding is the standard preprocessing step before optical character recognition: it removes paper texture and shading, leaving clean black text on white.

The right threshold depends on the scan. Too low loses faint strokes, too high fills in the gaps between letters.

Questions people ask

Is your image uploaded to a server?

No. This tool runs entirely in your browser using standard web APIs, so your image never leaves your device. You can confirm it by opening your browser's network panel while the tool runs, or by disconnecting from the internet after the page has loaded.

Is it free, and do I need an account?

Yes, it is free, and there is no account, no sign-up and no watermark on the result. The project is funded by optional donations.