What kind of photo works best?

Sign on plain white paper with a dark pen, photograph it flat in even light, and fill the frame. The tool handles moderate shadows and tint, but a clean shot gives cleaner edges.

Which ink color should I choose?

Auto-detect works for most photos. Pick 'Blue ink' or 'Black ink' to favor that hue when the paper tint is close to the ink color, and 'Red stamp / seal' for corporate seals and hanko.

Why does the preview show a checkerboard?

The checkerboard is the standard way to show transparency — anything you see through the ink is genuinely transparent in the PNG, not white.

How do I use the PNG to sign a PDF?

Click 'Open in Sign PDF' on the result screen — the PNG is saved to your signature library and Sign PDF opens with it ready to place. Or download the PNG and upload it in any signing tool.

Is my signature uploaded anywhere?

No. Extraction runs entirely in your browser on a local canvas — the photo and the PNG never leave your device.

Can I extract a company stamp or seal?

Yes — choose the 'Red stamp / seal' profile. The chroma-based extraction keeps saturated red ink while removing the paper behind it.

사진 속 서명과 도장에서 종이 배경을 제거하고 깨끗한 투명 PNG로 추출

종이 위에 찍힌 서명이나 도장 사진을 올리면 배경을 자동으로 제거해 깨끗한 투명 PNG로 만들어 줍니다. 파일은 업로드되지 않고 브라우저 안에서만 처리되는 무료 도구라, Sign PDF에 넣기 전 서명 이미지를 빠르고 안전하게 준비할 수 있습니다.

1. Photograph the signature

A phone photo of ink on paper — JPG or PNG, lighting doesn't have to be perfect.

2. Tune the extraction

Pick the ink color and adjust cleaning and edge contrast with a live preview.

3. Download or sign

Save the transparent PNG, or open it straight in Sign PDF to place it on a document.

From a phone photo to a usable signature

Ink on alpha, not ink on white

Signing a PDF with a raw photo leaves a white or yellowed rectangle floating over the document. This tool removes the paper entirely: it estimates the paper color from the photo's edges, then keys every pixel's transparency off how far its luminance and color sit from that background. The output is a transparent PNG where only the strokes remain.

Because the alpha ramp is continuous rather than a hard chroma-key cutoff, faint pen strokes keep partial opacity instead of snapping to fully-on or fully-off. That is what preserves the pressure texture of a real signature — the tapered start of a stroke stays tapered.

Tuned for real photos

Phone photos have shadows, wrinkles and uneven tint — the controls exist for them.

Ink color profiles

Auto-detect, blue ink, black ink, or red stamp — the extraction biases toward the hue you actually want.

Background cleaning

Bleaches white and yellowed paper, shadows, mold spots and wrinkles out of the alpha channel.

Edge contrast

Hardens stroke edges for a crisp stamp look, or softens them to keep faint pen pressure.

Straight into Sign PDF

One tap saves the PNG to your signature library and opens Sign PDF with it ready to place.

More than signatures

The same extraction works for corporate seals and hanko stamps (use the red profile), for line art you want to color digitally, and for any hand-drawn mark that needs to sit cleanly over another document. The result is trimmed to the ink's bounding box, so there is no dead transparent margin to fight when you place it.

Private by construction

The photo is decoded and processed on a local canvas — nothing is uploaded. A signature is biometric-adjacent personal data; it should never have to visit a server to be cleaned up.