# PDF to Grayscale - Convert a Colour PDF to Black and White Online

> Free online PDF grayscale converter: turn a colour PDF into grayscale or pure black and white, with adjustable threshold, brightness and live preview.

- URL: https://qilingtools.com/en/pdf/grayscale
- Category: PDF Tools (https://qilingtools.com/en/pdf)
- Tags: [PDF](https://qilingtools.com/en/tags/pdf), [Documents](https://qilingtools.com/en/tags/document), [Printing](https://qilingtools.com/en/tags/print)
- Last updated: 2026-10-26
- Price: Free, no sign-up
- Privacy: Runs locally in the browser; files are never uploaded

Convert a colour PDF to grayscale or pure black and white. Grayscale keeps the shading, which suits photos and charts; pure black and white keeps only two tones, and together with the threshold and contrast controls it cleans up yellowed or washed-out scans while shrinking the file noticeably. When a print shop charges by the colour page, converting first saves real money, and inkjets use far less ink. Page 1 previews live, so you can drag the sliders and see the result before committing. Everything runs locally and files are never uploaded.

## How to use

1. Upload a PDF file
2. Choose grayscale or pure black and white and tune the threshold, brightness and contrast against the preview
3. Pick a resolution and click Convert & download

## Features

- Grayscale and pure black-and-white modes
- Adjustable threshold, brightness and contrast
- Live page 1 preview — what you see is what you get
- Runs locally, never uploaded

## FAQ

### Is the text still selectable afterwards?

No. Changing colours pixel by pixel means the page has to be rendered first, so every page in the output is an image and the text can no longer be selected or searched. Avoid this tool if you need the text layer.

### How do I clean up a yellowed scan?

Pick pure black and white, raise the threshold until the grey background turns white, then add some contrast. If the writing fades too, lower the threshold again or raise the brightness — the preview shows it immediately.

### Why did my file get bigger?

A text-only vector PDF usually grows once converted to images. This tool is for scans and colour-heavy files; if you only want a smaller file, use Compress PDF instead.

### Are my files or data uploaded?

No. Everything runs locally in your browser with no network upload, and is discarded when you close the page.

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