❓ Frequently Asked Questions
What types of watermarks can this remove?+
This tool works on text watermarks, diagonal stamps (CONFIDENTIAL, DRAFT, SAMPLE), and colored overlays. It works by detecting the watermark color and erasing matching pixels across all pages.
Why is the tolerance slider important?+
Watermarks are semi-transparent, so the actual pixel color blends with the background. A higher tolerance removes a wider range of similar colors to catch all traces of the watermark. If normal content gets removed, lower the tolerance.
Will the output PDF have selectable text?+
The output is image-based — each page is rendered as a high-quality image. Text will look correct but will not be selectable. Use PDF OCR after if you need selectable text.
Are my files sent to a server?+
No. All processing happens entirely in your browser using PDF.js and pdf-lib. Your file is never uploaded anywhere.