Extract Signature & Stamp
Turns a JPG or PNG photo of a signature or stamp into a PNG with a transparent background by removing every pixel brighter than a level you set.
About This Tool
Extract Signature & Stamp takes a JPG or PNG picture of a signature or stamp on light paper and returns a PNG in which the paper is transparent. It works on brightness alone: every pixel brighter than the level you set becomes fully transparent, and every other pixel is kept.
The pixels that are kept are then strengthened. Reddish pixels get a stronger red, and dark pixels are pushed towards black, more so as you raise "Ink strength". "Kind of ink" decides whether this is chosen pixel by pixel or whether everything is treated as pen ink or as stamp ink. Edges are not smoothed, so the outline of the ink can look jagged, and a grey shadow darker than the level you set stays in the picture.
The preview shows the result as you move the settings; its chequered pattern stands for the transparent part. The picture keeps its size and nothing is cropped. Only JPG and PNG images are accepted, not PDF files. Everything happens in your browser; the picture does not leave your device.
How to Use
Upload the Picture
Choose one JPG or PNG of a signature or stamp. An evenly lit photo on white paper works best, because the tool separates ink from paper by brightness.
Choose the Settings
Pick one of the three options under "Kind of ink". "Remove paper brighter than" sets the cut: lower it to remove more grey, raise it to keep pale strokes. "Ink strength" darkens the ink that is kept; at 1 it is left as it is. Watch the preview as you change them.
Extract and Download
Click "Remove the background", then "Download". The download is your picture at its full size; the preview is a smaller copy of the same result. To try other settings, change them and run it again.
Use Cases
A Signature to Place on Documents
Turn a photo of your signature on white paper into a PNG with a transparent background, ready to be placed on a document.
A Red Stamp on Its Own
For a picture that shows only a red stamp, choose the red stamp option so that the red is strengthened and the paper removed.
Pen Drawings
Dark line drawings on light paper come out with the paper transparent, so they can be laid over another background.
Frequently Asked Questions
Can I see the result before I download it?
Yes. The preview beside the settings shows the result and changes as you move them; the chequered pattern stands for the transparent background. "Show the original" switches to your picture as it came in, to compare. The preview is a smaller copy, so open the downloaded PNG to judge fine detail.
What do the three options in the dropdown do?
They decide how the pixels that are kept are strengthened. "Automatic" treats clearly red pixels as stamp ink and everything else as pen ink. "Dark pen ink" treats everything as pen ink: pixels that end up clearly dark are pushed towards black, and lighter ones are left as they are. "Red stamp ink" treats everything as stamp ink: red is strengthened and green and blue are halved, so black ink and grey shadows take on a red tint.
Why is the edge jagged, or why did grey patches turn black?
A pixel is either removed or kept; nothing is made partly transparent and edges are not smoothed. If grey paper remains, lower "Remove paper brighter than"; if pale strokes disappear, raise it. Grey patches turn black when a shadow is dark enough to be kept and "Ink strength" is high: the tool cannot tell a shadow from ink, so it darkens both. Lower the strength, or take the photo again in even light.