How Stamp Extraction Works
A stamp is usually a colored ink mark pressed onto paper. Our tool separates that ink from the background using a color-confidence algorithm, then rebuilds the stamp as a transparent PNG that keeps the original ink density.
Analyze the stamp color
The algorithm converts the image into HSV and LAB color spaces and measures how strongly each pixel matches the target stamp color. This is more reliable than a single RGB threshold, especially for faded or unevenly pressed ink.
Build a soft confidence mask
Each pixel gets a confidence value instead of a hard on/off decision. Strong ink becomes opaque, light edges stay soft, and the paper background becomes fully transparent — preserving the natural look of the stamp.
Output a transparent PNG
The masked pixels are written to a PNG with an alpha channel. The result keeps the stamp's real colors on a fully transparent background, ready to place on documents, designs, or presentations.
Which Stamp Colors Are Supported?
Red and blue are the most common stamp colors and work with a single click. For everything else, sample the exact color straight from your image.
Red stamps
One-click preset for the classic red company seal, contract chop, and rubber stamp.
Blue stamps
One-click preset for blue ink stamps, notary marks, and received-date seals.
Custom color
Pick any color directly from the image for purple, green, black-red, or faded inks that presets may miss.
Faded and light ink
The confidence mask keeps soft, lightly pressed strokes instead of dropping them, so faded stamps still extract cleanly.
Common Use Cases for Stamp Extraction
Isolating a stamp as a transparent PNG is useful whenever you need to reuse, archive, or showcase a seal without the paper behind it.
Reuse a company seal
Extract your own company chop once, then place it on templates, invoices, or internal drafts without re-scanning every time.
Archive scanned contracts
Separate the seal from a scanned contract or receipt so you can keep the mark apart from the page.
Design and mockups
Drop a clean transparent stamp onto posters, presentation slides, product mockups, or UI samples.
Recover faded scans
Bring back a faded or lightly pressed stamp from an old scan, keeping the soft ink strokes a hard threshold would drop.
When to Crop the Stamp Area
Cropping is optional — the full image works out of the box. Crop the stamp area when the stamp is small, when the page contains other colored elements (logos, highlights, colored text), or when you want the algorithm to focus only on the region you care about. The cropped area is used exactly as you set it, with no automatic padding.
Our Own Algorithm, Not AI
Stamp extraction is built on our own deterministic color-confidence algorithm. We do not use AI recognition, and we never use your images to train a model.
Why deterministic matters
A rule-based color algorithm gives the same output for the same input, so results are predictable and easy to reason about. It also runs fast and keeps your data private, because nothing is sent to a third-party AI provider and nothing is retained for training.
Use This Tool Responsibly
Only extract stamps from documents you own or are authorized to reproduce. Stamps and seals can represent ownership, authenticity, approval, or legal effect. Misusing an extracted stamp may violate law or agreement — review the result before downloading and use it responsibly.