Remove PDF Background
Upload a PDF, set the brightness threshold and mode, then download a cleaned PDF.
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1Enter data
Enter content, paste text or load a file from disk. -
2Click the button
The tool will immediately process your data in the browser. -
3Get the result
Copy the finished text or save the file to your device.
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Other tools you may find usefulHow to Remove a PDF Background – Step by Step
Removing a PDF background comes down to three decisions: how aggressively to remove light pixels, what to do with the rest of the image, and what resolution to use for the result. The steps are straightforward.
- Choose a PDF file – select the document you want to clean up by removing its light background.
- Set the brightness threshold – the slider ranges from 120 to 245, and the default is 200. The current value is shown next to the slider.
- Choose a mode – color mode is active by default and preserves the colors of the content. You can also choose grayscale or black-and-white mode.
- Set the resolution – 100, 150, or 200 DPI. The default is 150.
- Click “Remove Background” and wait for processing to finish.
- Download the result – the new document is saved as no-background.pdf. Next to it, you will see the number of processed pages and the file size in kB.
If your PDF has more than 150 pages, a limit message will appear.
How the Brightness Threshold Works and the Pixel Brightness Formula
Each pixel has a brightness on a scale from 0 (black) to 255 (white). The tool calculates it using this formula:
L = 0.299 × R + 0.587 × G + 0.114 × B
R, G, and B are the color components of a given pixel. The result, brightness L, determines whether the pixel will be turned white.
There is one rule: if L is greater than or equal to the threshold you set, the pixel becomes white – all three components take the value 255. Pixels darker than the threshold are saved according to the selected mode.
What this means in practice:
- A lower threshold turns more pixels white – not only the background but also lighter parts of the content may disappear.
- A higher threshold turns fewer pixels white – a light background may remain visible.
The safest approach is to start with the default 200 and adjust the value based on the result. If the background is still visible, lower the threshold. If light content elements start to disappear, raise the threshold.
Color, Grayscale, and Black-and-White Modes, and JPEG vs PNG Differences
The mode determines what happens to pixels darker than the threshold.
| Mode | What happens to pixels below the threshold | When it is useful |
|---|---|---|
| Color | They stay unchanged – only the light background disappears | Color scans, stamps, highlights, charts |
| Grayscale | They are converted to shades of gray, in proportion to their brightness | When you care about readability of details without color |
| Black-and-white | They become either black or white – no halftones | Plain text and documents that should be as small as possible |
In grayscale mode, all color components take the same value based on the pixel's brightness: the darker the pixel, the darker the shade. Color disappears from the image, leaving a readable drawing in shades of gray.
In black-and-white mode, there are no halftones. Pixels clearly darker than the threshold become black, and those that are lighter but still below the threshold become white. This is classic binarization: strong contrast, a simple look, and the smallest file.
There is a difference in saving: black-and-white mode saves pages as PNG, meaning no lossy compression, so letter edges stay sharp. The other modes use JPEG compression, which gives smaller files but can slightly soften edges in high-contrast areas.
150-Page Limit, Page-to-Image Conversion, and No Text Selection
The tool processes up to 150 pages. If the file has more, you will see a limit message, and the result will include the first 150 pages. Split a longer document into smaller parts and process them separately.
Each page is converted to an image at the selected resolution. The resulting PDF has no text layer – it is a set of page images. In practice, this means you cannot select text, copy a paragraph, or search for a phrase: everything you see is an image.
Resolution affects the trade-off between quality and file size:
- 100 DPI – fastest processing and smallest file, but small print may be hard to read.
- 150 DPI – the default setting, a good compromise for most documents.
- 200 DPI – the sharpest image and largest file, useful for small text.
Limitations: What This Tool Won't Do
The tool removes light backgrounds and nothing more. It helps to know where its capabilities end.
- Dark backgrounds remain. Anything darker than the threshold appears in the result unchanged. Lowering the threshold helps only up to a point – dark or photographic backgrounds will remain.
- Light content may disappear along with the background. White letters, a pale stamp, or a delicate chart line will be turned white if their brightness exceeds the threshold. A higher threshold helps in that case.
- No text recognition. The tool does not run OCR, so it will not recreate a text layer or make the result searchable.
- No deskewing. A crooked scan will stay crooked – the tool does not rotate, crop, or align pages.
- Uneven scan lighting. If the background is lighter or darker in different areas, one threshold will not remove it evenly, and some of it may remain visible.
- File format. PDF documents are supported. Image files and documents in other formats will not be accepted.
Before continuing to work, review a few pages of the result – especially those with graphics, stamps, and light print – and check that nothing important has been turned white. If it has, change the threshold or mode and process the file again.
Processing happens in your browser, and the file is not sent anywhere. Processing time depends on the number of pages, the selected resolution, and your device's capabilities.
Frequently Asked Questions
Can I remove the background from a scanned PDF?
Yes, as long as the background is light and brighter than the threshold you set. With scans that have uneven lighting or a dark background, some of the background may remain. In that case, it is worth trying a few threshold settings and modes.
Is my file uploaded to a server?
No. Processing happens in your browser, and the document is not sent anywhere. This means confidential scans never leave your computer.
What brightness threshold should I use?
Start with the default 200. If the background is still visible, lower the threshold. If light parts of the content start to disappear, raise the threshold. Values near 120 turn a lot of pixels white, while values near 245 turn very few white.
Why can't I select text in the resulting PDF?
Because the pages are saved as images. The tool does not recreate a text layer or recognize characters, so the result behaves like a scan.
What should I do if my PDF has more than 150 pages?
The first 150 pages will be processed, and a message on the page will inform you about the limit. Split the longer document into smaller files and process them one by one.
Which mode should I choose: color, grayscale, or black-and-white?
Choose color when you want to keep colored elements, such as stamps, highlights, and charts. Choose grayscale when readability without color matters. Choose black-and-white for plain text and documents that should take up as little space as possible.
See also — related tools
Processing happens locally in your browser; check the current limits and any platform pricing on webp.pl.