# Grayscale image

Turn an image grayscale, black and white, using proper luminance weighting, not a flat channel average. Free, and nothing is uploaded.

Canonical page: https://filetity.com/grayscale-image

## Capabilities

- Free: Yes, with no watermark and no page limit.
- Account required: No. There is no account system.
- Processed on device: Yes. The file is read by your browser and never uploaded. There is no server to send it to.
- Formats: JPG, PNG and WebP in. The same format out, so nothing else about the file changes.
- Limits: No image count limit. Very large images are bounded by the memory your browser gives a canvas.
- Mobile: Yes, on any modern mobile browser. Large files are limited by the memory the phone gives the browser.
- Offline: Yes, after you have used it once. Your browser keeps what the tool needs, so it then works with no network connection.

## Questions

### Why do some black and white converters look flat?

Because they average the red, green and blue channels equally. To an eye, green is roughly five times brighter than blue, so an average renders a vivid green leaf and a deep blue sky as near-identical grey. This page uses the Rec. 709 weights that sRGB is defined against, which keeps the contrast that was actually there.

### Is this the same as removing saturation?

Close, but not identical. Desaturating in some editors uses a different formula, often the midpoint between the lightest and darkest channel, which produces a flatter picture. Luminance weighting is the version that matches how the scene looked.

### Can I get the colour back afterwards?

No. Converting to grey discards the colour information, so keep the original if you may want it. This tool never overwrites your file, it produces a new one.

### Does transparency survive?

Yes. Only the red, green and blue values are replaced; the alpha channel is not touched, so a PNG with a clear background keeps it. A JPG has no alpha to begin with, so nothing changes there.

### Can I do a batch?

Yes. Several images at once, each staying in its own format, delivered as a ZIP with -grayscale on each name. A JPG is re-encoded at quality 92 on the way out; a PNG is written exactly.

## Related tools

- [Invert image colors](https://filetity.com/invert-image-colors): Flip every colour in an image to its opposite.
- [Blur image](https://filetity.com/blur-image): Apply an adjustable blur to an image.
- [Image Compressor](https://filetity.com/image-compressor): Compress an image to a size you name, or to a quality you pick, and see the real result before downloading.