As an architect I regularly needed to send out drawing sets with a discreet studio logo on every sheet, as both branding and a basic layer of protection against misuse. Doing it sheet by sheet in Acrobat is slow, and most free tools either rasterize the result or handle multi-file batches poorly. The logo watermark tool processes any number of PDFs at once and outputs a ZIP. You can find it here.
The logo is automatically converted to grayscale before embedding, which keeps it neutral against any drawing background and avoids color conflicts with drawing content.
STEP Load your PDFs and your logo image
Open the Logo watermark tool and click Choose PDF(s). You can select an entire drawing set at once — ten, fifty or more files. Once loaded, the button confirms how many PDFs are ready.
Then click Choose image and select your logo file. PNG with a transparent background works best. JPG is also accepted. The tool will convert it to grayscale automatically, so the original colors of your logo file do not matter.
STEP Adjust opacity, size, rotation and position
Four parameters control how the logo appears on each sheet:
- Opacity — a value between 0.05 and 1. For a background stamp on working drawings, 0.10 to 0.18 is usually enough to be readable without interfering with drawing content. For a title page or cover sheet, 0.30 or higher works well.
- Scale — as a percentage of the page width. 40% places a centered logo that reads clearly on A1 or A0 sheets. Reduce to 20–25% for a corner logo.
- Rotation — in degrees. A slight diagonal angle (around -30°) is a common choice for central watermarks. For corner positions, 0° tends to look cleaner.
- Position — center, bottom right, top left, top right or bottom left. Center with a diagonal rotation is the standard for a discreet full-sheet stamp. Corner positions with 0° rotation work for a persistent logo mark.
The same settings apply to every page of every PDF in the batch. If you need different settings for a cover sheet and the rest of the set, process them as two separate runs.
STEP Apply and download the ZIP
Click Apply logo and download ZIP. Each PDF is processed in turn and packaged into a single ZIP file that downloads automatically. The original file names are preserved so the set stays organised. The entire operation runs in your browser — no files leave your device at any point.
A few practical notes
PNG logos with a transparent background produce the cleanest result. If your logo has a white background, it will appear as a white rectangle on the drawing. In that case, either use a PNG with transparency, or increase the rotation so the rectangle shape is less noticeable at low opacity.
The grayscale conversion uses luminance weighting, so a logo with strong contrast in its original colors will still read clearly after conversion. A logo that is mostly mid-gray at the same luminance level as the drawing background may become harder to read — in that case, try a slightly higher opacity or a corner position.