When this tool is useful
Preparing monochrome drafts, neutral reference images, printable handouts, and reduced-color visual assets.
How local processing works
The browser decodes the image, converts each pixel's color channels to a luminance-based gray value while retaining alpha, then encodes a new file in the source format.
How to use it
- Choose the source files.
- Review the available settings and page order.
- Process locally, inspect the result, and download it.
Important limitations
Discarded color cannot be recovered from the output. Files are re-encoded, metadata and animation are not preserved, and this is not a calibrated prepress color-conversion workflow.
Private by design
Your files stay in this browser. The tool does not upload the source or output to our servers.
Questions and answers
Does this tool upload my files?
No. Processing happens in your browser; closing the page clears the working session.
Will the output always match the source exactly?
Discarded color cannot be recovered from the output. Files are re-encoded, metadata and animation are not preserved, and this is not a calibrated prepress color-conversion workflow.
Concrete input and output example
Input a transparent 1200×800 PNG illustration and convert it to grayscale. The exported PNG keeps supported alpha pixels, but all color information is intentionally discarded and cannot be recovered from that copy.
Browser compatibility notes
Reviewed against the implementation and required web APIs on 2026-08-12. Use a current browser where these APIs are available and verify important output on your device.
- Chrome / Edge (current desktop)
- Requires local decode, canvas, encoding, Blob download, and enough memory; verify the downloaded image.
- Firefox (current desktop)
- Uses the same standard local APIs; color rendering can differ slightly from Chromium.
- Safari (current desktop)
- Uses canvas and Blob downloads; available memory and codec behavior remain WebKit-controlled.
A tool-specific question
Can I restore the original colors later?
No. The grayscale download no longer contains the discarded color channels. Keep the original image if color may be needed again.