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PDFに無料でオンラインで透かしを追加する方法

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What Is a PDF Watermark?

A PDF watermark is text or an image overlaid on every page of a document. Watermarks typically appear semi-transparent across the page content, marking the document as "Draft," "Confidential," "Sample," or displaying a company name.

Watermarks serve as visual identifiers that persist even when the document is printed or shared.

Why Add Watermarks to PDFs?

Watermarking protects and identifies your documents:

1. Protect Intellectual Property

Marking documents as "Confidential" or adding your company name discourages unauthorized redistribution.

2. Mark Document Status

Labels like "Draft," "Review Copy," or "Final" clearly communicate the document stage to recipients.

3. Brand Your Documents

Adding your company name or logo to every page reinforces brand presence in shared reports, proposals, and presentations.

4. Deter Unauthorized Use

Visible watermarks make it obvious when a document is copied without permission, discouraging misuse.

How to Add a Watermark to PDF — Step-by-Step Guide

Watermark your PDF in seconds:

Step 1: Open the Watermark PDF Tool

Navigate to the Watermark PDF tool in any browser.

Step 2: Upload Your PDF

Drag and drop your PDF document into the upload area.

Step 3: Configure Your Watermark

Type your watermark text and adjust the font size, opacity, color, and rotation angle to match your needs.

Step 4: Download Watermarked PDF

Click Apply and download your watermarked document. Your file never left your device — 100% private.

Watermark Tips & Best Practices

Use Semi-Transparent Text

Set opacity to 20-40% so the watermark is visible but does not obscure the underlying content.

Position Diagonally

Diagonal watermarks across the center of the page are hardest to remove and most effective as deterrents.

Choose Appropriate Text

Use short, clear labels: "CONFIDENTIAL," "DRAFT," "SAMPLE," or your company name. Avoid long sentences.

Common Use Cases

PDF watermarking serves many business needs:

  • Law firms marking draft contracts before finalization
  • Publishers watermarking review copies of manuscripts
  • Companies branding internal reports and proposals
  • Real estate agencies marking property listing documents
  • Teachers watermarking exam papers and study materials
  • Freelancers protecting portfolio samples sent to potential clients

よくある質問

How do I add a watermark to a PDF for free?+
Open the Watermark PDF tool on EasyTools24, upload your PDF, type your watermark text, adjust settings, and download. Completely free, no registration.
Is it safe to watermark PDFs online?+
Yes. The Watermark PDF tool processes your files entirely within your web browser using pdf-lib. Your files are never uploaded to any server, stored, or transmitted. The tool is 100% private and GDPR-compliant by design.
Can I remove a watermark after adding it?+
Watermarks are permanently embedded into the PDF. Keep a copy of the original unwatermarked file if you may need it later.
Does the watermark appear on every page?+
Yes. The watermark is applied across all pages of your PDF document with consistent positioning and appearance.

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