Sharpen a PNG without fringes
| Setting | Here | Photograph default |
|---|---|---|
| Radius | 0.5 px | about 1 px |
| Threshold | 0 | 3 levels |
| Transparency | Filled from the edge before blurring | Not applicable |
| Format | PNG | Same as opened |
Related on this site
- For a compressed photograph: sharpen a JPG.
- For a screenshot of text that has gone soft: deblur text in an image.
- For full control of the three numbers: unsharp mask online.
Questions: sharpen a png
Why does sharpening a logo give it a dark outline?
Because the colour of a fully transparent pixel is invisible and is usually stored as black. A blur that reads it pulls the visible edge towards black, and the sharpen then draws that as a dark fringe. This page fills the hidden colour from the visible edge before any blur, so the edge is sharpened as it is seen.
Is the transparency changed?
No, unless you ask. Alpha is carried across exactly by default. For a logo whose cut-out edge is itself soft, Sharpen the alpha edge too runs the same mask on the transparency.
What settings suit a screenshot?
The page opens with a 0.5-pixel radius, no threshold and luminance only, which steepens text and UI lines without ringing. The loupe opens at 200 % with smoothing off, which is how pixel-exact images should be judged.
Is the result a PNG?
Yes: lossless, at the same size, never flattened onto a background colour.
