Smart Sharpen in Photoshop CC 2014 creates artefacts in areas of bright highlights

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I've discovered an odd sharpening problem in Photoshop CC 2014 running on Mac OS X 10.10.3. I've managed to replicate this problem on three different people's Macs now, so we're pretty sure that this is problem in Photoshop rather than on just a specific machine. I haven't been able to test it in older versions of Photoshop.

In images that have large areas of bright highlights, using the Smart Sharpen filter can create weird artefacts in those highlights. Take the first image here as an example:



The artefacts created by Smart Sharpen are subtle, but noticeable in prints. Using an extreme Levels adjustment to exaggerate the artefacts makes them very obvious:



If I've successfully uploaded these screenshots in the right order, here are the Smart Sharpen settings being used:



Interestingly, if I turn on Legacy Mode in the Smart Sharpen dialog, the problem goes away.

This problem can be replicated on a wide variety of images: they just need to have areas of bright highlights like this.

Is this a known problem? We're working around it by using the Legacy Mode option in the Smart Sharpen dialog, but would be glad to help if we can provide any more useful information.
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Tom Catchesides

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Posted 3 years ago

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Steve Sprengel, Champion

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Is this a raw image or a JPG or a TIF? Is there one you're willing to share publically, by uploading to www.dropbox.com and posting a public share link, here?
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Steve Sprengel, Champion

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Not having an image to work with, I created a New Photoshop document 1000x800 pixels with a White background using RGB 8-bit and a ProPhotoRGB profile.

I applied a Smart Sharpen using your example parameters, then adjusted the gamma in Levels to 0.01 and I still see pure white, without any blocks or lines of areas slightly darker than pure white.

Therefore I cannot replicate the issue with an artificial document on my Windows 7 64-bit with PS-CC-2014.

My question about file format and request for an example are ways of seeing if the original image, itself, has these artifacts or not, prior to using Smart Sharpen. If SS is merely accentuating flaws in the background then that isn't a bug, I don't think.

If you feel that the image, itself, doesn't matter, as long as there are areas of white, then I'd suggest you try what I did and create a new blank PS document that is all white and test SS, there.

It is possible this is a Mac-only issue that I cannot replicate on my PC.

Here is the result of a second test where I drew some wide black lines across the image in case SS needs an edge to cause the artifacts but still nothing:
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Tom Catchesides

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Thanks for the reply, Steve!

I've uploaded a cropped version of the image I used in the first post so that you can try it out for yourself:

https://dl.dropboxusercontent.com/u/7...

The key ingredients seem to be large areas of white or near-white highlights, with darker parts of the image to the left of those areas.
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Steve Sprengel, Champion

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The artifacts are already in the image you've uploaded to Dropbox. If this image is before Smart Sharpen has been used, then the issue has nothing to do with Smart Sharpen other than it is accentuating the file details which is what it's supposed to do. This has to do with your camera and JPG compression most likely.

If you don't want to see these lines, then clip the very top few values from the top of the histogram by moving the whites slider down from 255 to say 252 in this example.

Here is what I see when I apply the Levels Gamma=0.01 to the image on Dropbox:
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Chris Cox

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Agreed - the lines are already in the image, and sharpening exaggerates the lines.

They could be from a lossy compression (like JPEG), or a previous processing step.
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Tom Catchesides

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Thanks for taking the time to look into this. I must have messed up with the sample file that I uploaded earlier, and now I'm out of the office for a while.

I'm not going to be in a position to be able to upload a correct example file until Friday, but will do so as soon as I get back into the office.
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Steve Sprengel, Champion

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If you're going to share a cropped version of your image before using Smart Sharpen, then save it as PNG or TIF, something that won't have compression artifacts like JPG will.