Find the first file that actually contains the box
Keep the source photo, your prepared asset, and the version inserted into the document separate. Open the prepared asset over a coloured background rather than a white page. If the rectangle appears there, the problem is in the image or its export. If it appears only after insertion, investigate the receiving application or the file it accepted.
Use a coloured area with a clear boundary, such as a grey rectangle beside a white rectangle. A genuinely transparent area shows whichever colour is underneath it. Do not diagnose transparency from a white thumbnail alone. Some viewers display a transparent file on white, and some display a checkerboard; neither display choice changes the stored image.
Separate leftover paper from a solid export background
An evenly rectangular white patch reaching all four image edges suggests a solid background was included. An uneven patch hugging the handwriting suggests that some photographed paper remains in the mask. These need different fixes: change the export background for the first, and revisit the mask for the second.
PNG and WebP can carry alpha transparency, but both can also store opaque images. Naming a file “signature-transparent.png” or changing its extension does not remove white pixels. In Paperkiss development builds, the export dialog separates the format from the background choice. Check both settings rather than assuming the format automatically chooses transparency.
Export from the prepared asset, not a screenshot
Return to the prepared signature or its saved library item. Export PNG with the transparent background option. Avoid taking a screenshot of a preview: the screenshot captures the preview surface together with the ink. Likewise, a picture copied from a white document page may already include that page background.
If the available file is JPG, it is not a reusable transparent result in the Paperkiss workflow. Open the earlier prepared master if you have it. Otherwise, treat that JPG as a photograph and prepare its background again. Keep the new PNG as a separate file so you can compare the results and avoid overwriting your only reference.
Fix residual paper without erasing the signature
If only a fringe or irregular patch remains, inspect the signature on a dark background in the photo studio. Increase background removal cautiously and use local erasing for isolated paper. Restore genuine thin strokes if a cleanup step removes them. The target is clear space around the original ink, not a narrower or redrawn signature.
Look inside closed loops as well as around the outside. A tiny white island inside an “a” or a flourish may be difficult to see on a white page but obvious on a coloured form. Do not fill the loop with darker ink to hide the patch. Remove its paper pixels while keeping the surrounding stroke intact.
Check what the receiving workflow preserves
Insert the repaired asset into a disposable copy of your target document. Position part of it over a shaded area and inspect the edge. If transparency worked in the asset but fails here, try importing the image file directly instead of copying a preview or using a clipboard intermediary. Check the destination application’s supported image formats.
Paperkiss is still in development; its intended workflow places prepared image artwork locally and exports a new document copy. Once you have a finished PDF, inspect that PDF rather than relying only on the editor preview. If you must provide a flattened image to another system, choose its background deliberately and keep your transparent master for later reuse.
Questions and answers
Does a white thumbnail mean the signature is opaque?
No. The viewer may simply use white behind transparent pixels. Test the actual file over a coloured surface before changing its mask.
Will saving a JPG as PNG remove its white background?
No. Conversion can preserve the existing white pixels. Prepare the background first and then select transparent export; changing the format alone does not create a mask.
Why does the edge look white only on a dark page?
A pale fringe may contain leftover paper or light edge pixels. Compare with the source and adjust the local mask carefully instead of erasing every soft boundary.