Why image stamping is a frequent PDF task
Adding a company logo to every page of a contract, placing a signature block across a batch of invoices, or overlaying a 'DRAFT' proofing mark on a presentation are all tasks that come up constantly in business workflows. Manual stamping in a desktop PDF editor works for a single document, but when you need to process dozens or hundreds of PDFs, the per-click overhead becomes a real bottleneck.
The core challenge is positioning: the stamp needs to appear at a consistent location relative to each page, regardless of whether the pages are portrait, landscape, letter, or A4. Anchor-based positioning solves this by letting you choose a reference point like 'top-right' or 'bottom-center', and the tool calculates the exact coordinates from the page dimensions.
Transparency control through the opacity slider adds another layer of utility. A fully opaque logo might obscure text beneath it, while a semi-transparent watermark at 20% opacity protects the document without making it unreadable. The five anchor positions cover the most common placement needs without requiring you to enter pixel coordinates manually.
Stamp placement options
| Anchor Position | Placement | Common Use |
|---|---|---|
| Top-left | Upper left corner | Company logo, letterhead |
| Top-right | Upper right corner | Confidential stamp, branding |
| Bottom-left | Lower left corner | Signature, date stamp |
| Bottom-right | Lower right corner | Approval seal, footer logo |
| Center | Page center | DRAFT overlay, watermark |
How to stamp a PDF with an image
Drop your PDF file into the left upload zone and your stamp image (PNG or JPG) into the right upload zone.
Choose one of the five anchor positions where the stamp should appear on each page.
Adjust the stamp size as a percentage of the page width using the size slider. A 15% width logo on a letter-size page produces a roughly 1.5-inch wide stamp.
Set the opacity with the opacity slider. Full opacity (100%) is ideal for logos, while 10-30% works well for watermarking.
Adjust the margin if you want the stamp inset from the page edge rather than flush against it.
Click 'Stamp every page' to process the PDF and download the result.
Testing your stamped PDF
Open the downloaded PDF in a viewer that renders at 100% zoom, such as Adobe Acrobat Reader or Chrome's built-in PDF viewer. Verify that the stamp appears on every page at the expected position and that the opacity level matches what you selected. Check both a portrait page and a landscape page if your PDF contains mixed orientations, since the anchor positioning adapts to each page's dimensions.
If you used a transparent PNG, confirm that the transparency is preserved in the output — the area around the stamp content should show the underlying PDF content cleanly. Compare the file size of the stamped PDF against the original; the increase should be proportional to the image size, not dramatically larger.
Common mistakes
Using a very large stamp image: a 4000×4000 PNG embedded at full page width will bloat the PDF file size significantly. Resize the stamp image to approximately the dimensions you need before uploading.
Stamping a PDF that already has a watermark: the tool applies the stamp on top of existing content without removing anything. If you need to replace an old watermark, remove it first with a PDF editor.
Expecting per-page control: this tool stamps every page uniformly. If you need the stamp on only specific pages, extract those pages first and stamp them separately.
Forgetting margin adjustments: without a margin, the stamp sits flush against the page edge, which may look odd on documents with generous existing margins.
PNG transparency and format handling
PNG files with transparent backgrounds are the ideal stamp format because the transparency is preserved when embedded in the PDF. This means a logo with a transparent background will let the PDF content show through the empty areas, creating a clean overlay effect. The opacity slider then applies additional transparency on top of the PNG's built-in alpha channel.
JPG images do not support transparency, so a JPG stamp will always have a solid rectangular background. If you only have a JPG of your logo, convert it to PNG first with a background removal step. Other formats like WebP, GIF, and BMP are automatically converted to PNG via a canvas element before embedding, so the tool handles them transparently.
Real-world use cases
Adding a company logo to the header of every page in a 40-page proposal PDF before sending it to a client, ensuring consistent branding throughout the document.
Placing a 'CONFIDENTIAL' watermark at 15% opacity in the center of every page of a financial report that needs to be shared internally but not distributed externally.
Stamping an electronic signature image onto the bottom-right of each page of a contract as a visual authentication mark before archiving.
Overlaying an 'APPROVED' seal on engineering drawings that have passed review, with the seal positioned at top-right for visibility.
Frequently asked questions
Q: Which image formats work as stamps?
A: PNG and JPG work natively. WebP, GIF, and BMP are auto-converted to PNG via canvas before embedding in the PDF.
Q: Can I stamp only specific pages?
A: This tool stamps every page in the PDF. For per-page control, extract the target pages first, stamp them, then recombine.
Q: Does it support transparent PNGs?
A: Yes — PNG transparency is fully preserved. The opacity slider adds additional transparency on top of the image's own alpha channel.
Q: How is the stamp positioned on each page?
A: The stamp is anchored to one of five positions (top-left, top-right, bottom-left, bottom-right, center) and offset by the margin you specify. The position adapts to each page's dimensions.
Q: What size should my stamp image be?
A: The size is controlled by the percentage-of-page-width slider, so the image is scaled to fit. However, starting with a reasonably sized image (200-800px) keeps the PDF file size manageable.
Q: Does stamping change the original PDF content?
A: The original file is not modified. A new PDF is generated with the stamp overlay, and the original remains unchanged on your device.
Start stamping your PDFs now
Try the PDF Image Stamp tool to add logos, signatures, or watermarks to every page. See also Add PDF Watermark, Edit PDF, and PDF QR Stamp for more PDF editing options.
