I'm resizing photos uploaded to a photography gallery and have thus applied an unsharp mask to attempt to preserve the photos original sharpness. The settings I use are:

radius: 0 sigma: 0.5 amount: 1 threshold: 0.05

I have noticed in some cases that photos are appearing over sharpened. Particularly when photos have high contrast close together lines.

So, what are the best settings for the unsharp mask after resizing? something I can apply to any photo uploaded and get the highest % of correctness. I understand that occasionally one won't look correct.

  • \$\begingroup\$ Related: photo.stackexchange.com/questions/1370/… \$\endgroup\$
    – Guffa
    Mar 19, 2013 at 11:19
  • \$\begingroup\$ Just to clarify: the service you are uploading the images to isn't doing any further processing (such as resizing) of the images, is it? \$\endgroup\$ Mar 19, 2013 at 13:11
  • 1
    \$\begingroup\$ The answer would vary depending on output use(web, print), size, and content of the image. There are no "laws of sharpening", that I am aware of. \$\endgroup\$
    – dpollitt
    Mar 19, 2013 at 13:13
  • \$\begingroup\$ In this case, we know some of the variable: web view, and resized for viewing at 100% 1:1 pixel level. \$\endgroup\$
    – mattdm
    Mar 19, 2013 at 14:17

2 Answers 2


If the images are often appearing to be over-sharpened, but you haven't noticed images being under-sharpened, then it's a good sign that you are simply sharpening them too much.

Try decreasing the "amount" argument until you get more satisfactory results. For example, try halving it, then halving it again, until you notice that it's about right.

I suspect, however, that you may end up resorting to applying different amounts of sharpening to each one by hand, because what looks good for one image may not look good for another.


Instead of going for the best Unsharp Mask parameters, why not use something much better and more modern?

Usually I like to sharpen my photos in Multi Scale approach.
Namely, selecting different sharpening level (Amount in the Unsharp Mask window) for each detail scale (Size).
Something like equalizer.

I personally use Fixel Detailizer 2 PS since it is quite cheap.
Some use Topaz Detail, which is slower, yet great as well.


  • \$\begingroup\$ Can these "much better and more modern" techniques be done easily with ImageMagick? \$\endgroup\$
    – mattdm
    Mar 11, 2015 at 15:41
  • \$\begingroup\$ I'm not sure as I don't know ImageMagick that well. \$\endgroup\$
    – Royi
    Mar 12, 2015 at 6:32

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