Why transparent?
If you paste a plain photo of your signature into a document, the paper comes with it: a grey or off-white rectangle over the form's lines and text. A transparent PNG contains only the ink, so it overlays the signature line the way a pen would. It also lets you change the ink colour, and keeps the file small.
Step 1: sign and photograph
- Sign on plain white paper with a dark, bold pen. Sign a few times and pick the best.
- Photograph in daylight, phone held parallel to the paper, signature filling most of the frame.
- Avoid flash, which leaves a hot spot, and avoid your own shadow across the page; the tool handles mild shadows, but less is better.
Step 2: remove the paper
Open the transparent signature tool and load the photo. Signature mode does not use AI. It converts the image to greyscale and keeps pixels that are darker than their local surroundings: an adaptive threshold. Because it compares each pixel with its neighbourhood rather than with a fixed level, a shadow falling across half the page does not become part of the signature. Adjust Sensitivity until thin strokes are solid and the paper texture is gone. Pick an ink colour (black or a dark blue look most natural) and download the PNG.
Step 3: place it in the PDF
- Adobe Acrobat Reader: Fill & Sign lets you add a signature from an image.
- macOS Preview: open the PNG, copy it, open the PDF, paste, then drag and resize. Or use Markup's signature tool with the image.
- Microsoft Word or Google Docs: insert the image, set wrapping to "in front of text", then export to PDF.
- In the browser: the site's PDF sign tool places an image signature on any page, with no upload.
Size the signature to the line, usually 40 to 60 mm wide. If it looks pixelated when printed, photograph a larger signature or at a higher resolution.
Troubleshooting
- Broken or gappy strokes. The pen was too fine or the light too dim. Raise Sensitivity, or sign again with a felt-tip and photograph it in daylight.
- Grey speckles around the signature. Paper texture or a lined pad is showing through. Lower Sensitivity, or use the Remove brush on the specks.
- Lines from ruled paper. Blue or grey printed lines are darker than the paper, so they can be kept. Sign on blank paper instead; it is quicker than cleaning lines out.
- The signature looks jagged when printed. The photo was too small. Sign larger, fill more of the frame and use the HD export for the full resolution.
- The ink colour looks wrong in the PDF. Some viewers flatten transparency against a coloured page; pick black or navy ink, which reads well on any form.
Visual versus digital signatures
An image of your signature is a visual signature: evidence that you intended to sign, accepted for many everyday forms and agreements. It is not a cryptographic digital signature, which binds the signer's verified identity to the exact contents of the document and shows if anything changes afterwards. Some government forms, statutory declarations, property transactions and banking documents require a digital signature through an approved service, a witnessed wet-ink signature, or both. If in doubt, ask the person who will receive the document what they accept.
Keep your signature image safe
A clean, transparent signature is useful to you and to anyone who wants to forge it. Store it like any identity document, do not leave it in shared folders, and do not upload it to services you do not trust. The tool on this site processes it entirely in your browser; nothing is sent anywhere.