Stamping a PDF, applying a visual mark like 'Approved', 'Revised', 'Draft', or a custom firm seal, is one of the oldest digital workflows in architecture and construction. The stamp on a shop drawing tells the contractor it's been reviewed. The stamp on a permit set tells the building department it's been signed off. Done well, the stamp is permanent, scaled correctly, and renders identically across every PDF tool the recipient might use. Done poorly, the stamp is a low-resolution image that becomes a tile of pixels when the contractor zooms in. This page covers how to stamp PDFs cleanly, what makes a good stamp, and how Ncored handles the workflow.

What goes wrong with PDF stamps in general tools

Two common problems with stamps in free or general-purpose PDF tools. First, low-resolution stamp images that pixelate when the recipient zooms in for review. Most free online PDF stampers and some built-in stamp libraries use raster images at fixed pixel dimensions, fine at the original zoom level, terrible at 400% zoom on a contractor's screen. Second, stamps that don't travel correctly. Some PDF tools apply stamps as a tool-specific annotation type that the recipient's viewer may not render, leaving the stamped drawing without the stamp on the other side. The architect stamps, the contractor opens the file, the stamp is invisible. For drawings where the stamp is the legal or procedural signal, this is a real failure. The fix in both cases is to use a tool that renders stamps as standard high-resolution image annotations.

How Ncored handles PDF stamps

Ncored's stamp tool lets you add your own image stamps (for example your firm's seal, or an approval graphic you make), saved and reusable across projects. Use a high-resolution image so the stamp stays crisp when a contractor zooms to 400% for review. Each stamp is applied as a standard PDF annotation. Saved stamps render correctly when the file goes to a contractor or reviewer on Bluebeam, Acrobat, Foxit, or any compliant PDF tool. Pricing is €12.99/month or €79.99/year, on Apple Silicon Macs (macOS Big Sur 11+) and Windows 10/11. The 14-day trial needs no signup or email; after the trial an account and licence are required. If your seal or logo comes on a white background, one click removes the white so the stamp sits cleanly over the drawing with nothing boxed around it.

Your own image stamps
Add your own image stamps, for example your firm's seal or an approval graphic you make.
White background removed in one click
Upload a seal or logo that sits on a white box and remove the white with one click, so the stamp drops onto the drawing cleanly with no white block around it.
Saved and reusable
Each stamp you add is saved and reusable across projects.
Crisp at deep zoom
Use a high-resolution image so the stamp stays crisp when the recipient zooms in.
Stamps that travel correctly
Standard PDF annotations render correctly on Bluebeam, Acrobat, Foxit on the recipient side.

Try the 14-day free trial

Download Ncored

Ncored vs free online stamp tools vs Adobe Acrobat

Free online PDF stamp services should generally not be used for confidential project drawings, the file is uploaded to a third party, the stamp quality is often low resolution, and the result may not travel cleanly to downstream viewers. Adobe Acrobat Pro has a strong stamp tool with both vector and image support; it handles the workflow well at the $240/year subscription cost. Bluebeam Revu has the deepest construction-specific stamp library and customization, particularly for construction-specific workflows. Ncored covers the practical middle: stamps render as standard PDF annotations, the workflow is fast on heavy drawings (no lag when applying stamps across a 50-200 MB+ project set), and the price is well below either Adobe or Bluebeam. For pure stamping use cases on a Mac at small studio scale, Ncored fits cleanly.

Frequently Asked Questions

Can I use a stamp with my firm's logo?
Yes. Add your own image stamps, for example your firm's seal, or an approval graphic you make. The stamp is saved and reusable across projects.
Will my stamps render correctly when I send the PDF to a contractor on Bluebeam?
Yes. Ncored's stamps are written as standard PDF annotations, Bluebeam, Acrobat, Foxit all render them correctly with the same visual quality.
Do stamps stay crisp at deep zoom levels?
Stamps are based on the image you upload, so crispness depends on the source image resolution. For crispness at high zoom, use a high-resolution image source.
Can I reuse the same stamp across a multi-page PDF?
Yes. Your stamps are saved and reusable, so you can place the same stamp on each page you need it on. Navigate the multi-page set using the thumbnail panel.
Is the stamp permanent, can the recipient remove it?
By default the stamp is written as a standard PDF annotation, so like any annotation it can still be moved or deleted in a PDF editor. To make a stamp permanent, use Flatten & Compress from the File menu: it bakes annotations and stamps into the page content so they become part of the drawing and can no longer be selected or removed. Ncored saves with an atomic, crash-safe write, so the stamped file is never left corrupted mid-save. If you need to hide confidential content rather than mark it, Ncored's redact tool covers the chosen area and burns it permanently into the PDF, so the hidden content becomes part of the file and cannot be recovered.
My logo sits on a white box, will the stamp show a white block on the drawing?
No. When you upload it, one click removes the white background so the stamp drops onto the drawing cleanly, with nothing boxed around it. Handy for scanned seals and logos that come on a white background.