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Image threshold
Convert encoded-RGB weighted luminance to black or white at a chosen threshold.
PNG, JPEG, WebP
PNG
Browser only
Runs locally in your browser. Your files, pasted content and generated output are not uploaded. Reset clears this tool’s working data.
This tool needs JavaScript. If it does not load, refresh the page and try again.
How to use this tool
- Choose supported local images and set the controls for the operation.
- Select Process image, inspect the preview or report, and download the result.
- Cancel stops the worker. Reset clears selected files and restores the settings.
Examples
RGB 64,128,192 becomes black at threshold 128.
Limitations
- PNG, JPEG and static WebP only. 20 MiB and 24 megapixels per input, 16,384 pixels per side; output at most 24 megapixels and 64 MiB. Multi-image input totals at most 100 MiB. Processing runs in a cancellable worker with a 120-second deadline. Rendered PNG outputs use stored pixel orientation and browser-decoded colors, with no source EXIF/XMP/text copied.
- Threshold compares 0.2126 R + 0.7152 G + 0.0722 B against 0–255 using encoded RGB values, not linear-light luminance. Alpha is retained.
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