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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easytools24のPDF透かしツールで無料でPDFに透かしを追加できます。カスタムテキストやロゴを追加し、不透明度と位置を調整して、保護されたPDFをダウンロード。すべての処理はブラウザ内で完了します。
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?+
Is it safe to watermark PDFs online?+
Can I remove a watermark after adding it?+
Does the watermark appear on every page?+
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