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SigCleaner is a service for removing backgrounds from seals, stamps, and handwritten signatures. Here you will learn how to get the best results.

What SigCleaner does

SigCleaner helps make the background of a stamp or signature transparent on a photo or scan. You upload an image, the AI analyzes it and removes everything unnecessary: white or colored paper backgrounds, "L.S." and "Place for seal" marks, form lines and grids, shadows, and random artifacts.

The output is a PNG file with a transparent background — ready to insert into Word, Excel, Google Docs, PDF, InDesign, or any other program.

Use cases

Insert a company seal into an electronic invoice, certificate, or contract
Create a digital copy of an executive's signature
Prepare a "Paid", "Received", or "Accepted" stamp for a PDF
Remove the background from a stamp for legally binding electronic document management systems
Process a notary or bank seal for insertion into documents
Batch processing via API in corporate systems

How to use the service

1
Upload an image

Drag and drop a file onto the main page, click "Upload", or paste an image link. You can also take a photo of the stamp directly with your phone's camera — tap "Camera".

Supported formats: PNG, JPG, PDF. Maximum file size — 20 MB.

2
Select the stamp area

After uploading, the cropping tool will open. Crop the image so that only the stamp or signature remains in the frame, with a small margin around the edges.

The more accurately the area is selected, the better the result — extra parts of the document can confuse the algorithm.

3
Click "Remove Background"

The AI will process the image. This takes 10 to 60 seconds depending on complexity. While processing, a progress animation is displayed on the screen — do not close the tab.

4
Compare "before" and "after"

After processing, a comparison will open — drag the slider to see the original image and the result. If you are satisfied with the result — download the file.

5
Download PNG with a transparent background

Click the "Download PNG" button. The file will be saved to your device as a PNG with a transparent background, ready to be inserted into documents.

How to get the best results

Photo recommendations
  • Take photos in good lighting — avoid shadows and glare
  • Hold the camera directly above the document, not at an angle
  • The clearer the stamp impression — the more accurate the result
  • Use a scan if possible — the quality is higher than a photo
  • Crop the image so that the stamp takes up most of the frame
When the result might be worse
  • Very pale, faintly printed, or faded stamp
  • Stamp on a dark or colored background (not white paper)
  • Smudged or blurry photo
  • Large objects (text, other stamps) next to the stamp in the frame

Frequently Asked Questions

No. You can remove the background from a stamp or signature without registration — simply upload the image. Registration (via email) is only required for API access.

No. SigCleaner is completely free — no subscriptions, no watermarks, and no limits on the number of images.

The result is downloaded as a PNG with a transparent background. PNG supports transparency and is suitable for inserting into Word, Excel, Google Docs, Canva, PDF, and most other programs.

Yes. The service accepts PDF files — the first page is automatically converted to an image for processing.

Images are stored temporarily — only to allow downloading the result. After the retention period expires, files are automatically deleted. We do not share data with third parties.

Sign up (login via email code), get an API key in your account, and send POST requests to /api/clean with the header Authorization: Bearer <your-key>. Full documentation — on the page API.
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