Online Image Threshold Tool

What Online Image Threshold Tool does

Convert to pure black and white image by threshold

Worked example

How the pixels are processed

A luminance value is compared with the threshold and each pixel becomes pure black or white.

Useful workflows

• Prepare web graphics, product images, presentations or visual test fixtures.
• Compare the preview at 100% zoom before exporting the result.
• Keep consistent settings across related images.

Quality, privacy and compatibility checks

• Repeated lossy export can reduce quality; retain an original and choose an appropriate output format.
• Very large dimensions or batches can exceed browser memory even when total file size appears small.
• Metadata, color profiles, animation and transparency may not be preserved by every canvas export format.

Frequently asked questions

Is the source image uploaded?

The normal editor decodes and processes supported images in this browser without uploading them to an application server.

Why can the downloaded image look different?

Check output format, compression, color profile, transparency, dimensions and whether the browser applied orientation metadata.

What does the threshold value mean?

The threshold is a number from 0 to 255 (default 128). Each pixel's brightness is calculated as 0.299R+0.587G+0.114B. If that brightness is greater than or equal to the threshold, the pixel becomes white; otherwise it becomes black.

Can I process multiple images at once?

No, this tool processes one image at a time. There is no batch mode on this page.