How to Stamp a Company Seal on Many PDFs

The problem: the same seal, many files, two jobs

Finance and admin teams often need the company seal in two places. The signature page gets the whole seal. Every page also gets a slice of the seal on the right edge, so the slices form one seal again when the document is bound. That second mark is a cross-page seal, the PDF version of a 骑缝章.

Doing it by opening each PDF, dragging a PNG, and saving is fine for one contract. On a stack, the page number drifts, one slice gets skipped, or Save replaces the original file.

A worked example

You have 12 contracts. Each one is 6 pages. The signature seal goes on page 6 only, 30 mm from the right edge and 40 mm from the bottom. The cross-page seal is a 42 mm wide PNG, sliced across all 6 pages and placed 8 mm in from the right edge. Those distances are choices you write down once. They are not magic numbers.

Step 1: Count pages and placements

12 files × 6 pages = 72 pages
Signature seals: 12 files × 1 page = 12 placements
Cross-page slices: 12 files × 6 pages = 72 placements
12 + 72 = 84 image placements

By hand, that is 84 times you position the PNG, plus 12 saves. One missed page is a gap in the bound seal. One Save instead of Save As overwrites the unsigned original.

Step 2: Split the cross-page seal

The full seal has to come back when the pages are stacked. Divide its width by the page count of that file:

42 mm ÷ 6 pages = 7 mm per page
6 × 7 mm = 42 mm

One 42 mm seal, left to right, as six 7 mm slices. Page 1 gets the first slice.

Each slice is only the strip for that page, sitting on the right edge. If contract 7 is 6 pages and you stamp five of them, the bound edge shows five-sixths of the seal. 5 × 7 mm = 35 mm, so 7 mm of the seal is missing.

Step 3: Keep the original file

You still have 12 source files and 12 stamped files. The folder count doubles on purpose. Deleting or overwriting the source to “tidy up” is how you lose the unsigned copy.

Step 4: Reuse the same setup

The next batch is not a new design. It is the same PNG, the same page rule (last page, or a range such as 1,3-5 when the signature page is not always page 6), and the same edge distance. Write that down as a preset so file 1 and file 12 do not drift apart.

Tips for a stamp you can defend

• Start from a PNG with a transparent background. A white box around the seal covers the contract text.
• Fix the page range in writing. “Last page” and “page 6” are the same only when every file has 6 pages. A 4-page contract needs its own range.
• Measure the seal, then divide. Slice width = seal width ÷ pages in that file. Check that the slices add back to the full width.
• Set the distance from the right edge in millimetres. The same 8 mm on every page is what makes the slices line up when the document is bound.
• Write a new file. A suffix such as _已盖章 keeps the stamped PDF next to the original without replacing it.

Let PDF Batch Stamper apply the seal

Eighty-four placements is a dull afternoon and an easy mistake. PDF Batch Stamper is a Windows desktop app that applies one setup to the whole stack:

• Batch. Many PDFs in one run, with the same PNG seal.
• Position and page range. Place the seal and limit it to pages such as 6 or 1,3-5.
• Cross-page seal. The seal is sliced across the pages and placed on the right edge. You set the distance from the edge in millimetres. Bound together, the slices read as one seal.
• Templates. Save the position, the range, and the edge distance as a preset.
• New files only. The stamped PDF is a new file. The default suffix is _已盖章. Originals are not modified.
• Offline. PDFs stay on your PC. English and Simplified Chinese.

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