Over sharpening?

[William (Bill) Anderson]

I'm curious as to what others consider and/or look for as 'over sharpening' in a digital image, in either qualitative or quantitative terms. Thanks

 

[DRwyoming]

I'm curious as to what others consider and/or look for as 'over sharpening' in a digital image, in either qualitative or quantitative terms. Thanks

As posted above I'd start by looking for unnatural dark or bright halos around higher contrast edges as the first sign of over sharpening. But on a more qualitative level my last step when evaluating appropriate amount of sharpening is to look at things like green summer grass (if it's in your shot) or fur detail and ask myself whether is looks soft and inviting or looks like I'd cut myself on it. If the latter I've probably gone too far with the sharpening unless the subject really should look like a wire brush

A couple of caveats on sharpening.
- For print use I like to do my final sharpening evaluation at 50% zoom level and not 100% where you're really zoomed in close compared to normal print viewing distances.
- For web use where images will be viewed pixel for pixel on the screen I do my final evaluation at 100% (1:1) view as that's how the image will be viewed.
- Ideally final sharpening should be done after any resizing to final output size whether that's upsizing for a print or downsizing for screen use.
- One of the reasons I prefer PS to LR for processing print images is the ability to sharpen on a layer and then rapidly toggle the layer visibility (eyeball icon) on and off to see the impact of the sharpened layer and then tune down the opacity of that sharpened layer if I've gone too far. It's much easier to assess appropriate sharpening with that rapid before and after toggle than it is to see the difference when adjusting a slider and then having your eyes adjust to the new image.

And generally speaking if I'm on the fence over whether I have too much or just enough sharpening I'll err on the side of under sharpened as folks tend to accept a slightly soft image better than one with visible sharpening artifacts.

 

[Bristolian]

I concur with both of the above

 

[gordon_g]

As @Thern Said when you can see white outlines it's too much often much to much.

Some photos need more sharpening than others and some much less than others.. Hard to explain more a trial and error process. my recommendation would be to practice on some images after a while you will see very plainly what is over done and what is not. I almost alway tend to under sharpen just a bit. Really it starts with the image out of the camera, if there is any blur or I don't think it Sharp it goes in the trash... I only work on images that are sharp out of the camera to start with. (I view all images at 100% to ascertain if its sharp out of the camera)

 

[Strodav]

There are a lot of good comments here, but I would like to add that perceived sharpness is affected by contrast. If you can increase the contrast in the critical parts of your image you don't need as much sharpening so can avoid oversharpening. Another thought is that you can't really fix an out of focus or blurred image, say, due to camera shake, with sharpening. You can try, but it just makes things worse.

 

[Cristobal]

As posted above I'd start by looking for unnatural dark or bright halos around higher contrast edges as the first sign of over sharpening. But on a more qualitative level my last step when evaluating appropriate amount of sharpening is to look at things like green summer grass (if it's in your shot) or fur detail and ask myself whether is looks soft and inviting or looks like I'd cut myself on it. If the latter I've probably gone too far with the sharpening unless the subject really should look like a wire brush

A couple of caveats on sharpening.
- For print use I like to do my final sharpening evaluation at 50% zoom level and not 100% where you're really zoomed in close compared to normal print viewing distances.
- For web use where images will be viewed pixel for pixel on the screen I do my final evaluation at 100% (1:1) view as that's how the image will be viewed.
- Ideally final sharpening should be done after any resizing to final output size whether that's upsizing for a print or downsizing for screen use.
- One of the reasons I prefer PS to LR for processing print images is the ability to sharpen on a layer and then rapidly toggle the layer visibility (eyeball icon) on and off to see the impact of the sharpened layer and then tune down the opacity of that sharpened layer if I've gone too far. It's much easier to assess appropriate sharpening with that rapid before and after toggle than it is to see the difference when adjusting a slider and then having your eyes adjust to the new image.

And generally speaking if I'm on the fence over whether I have too much or just enough sharpening I'll err on the side of under sharpened as folks tend to accept a slightly soft image better than one with visible sharpening artifacts.

Very instructive

 

[William (Bill) Anderson]

A very interesting/informative thread.

 

[Pistnbroke]

If you shoot JPEG put the internal sharpness to +9 it gives no artifacts and gives a pleasant image.

 

[Calson]

Often sharpening is done too early in the post processing and I always adjust levels, then contrast, and the very last step is sharpening after the archived image has been resized. The smaller the output size the more I sharpen and image which is why I always return to the "original" file and then resize and sharpen. If the image is for a 400 x 400 ppi image it is sharpened far more than for a 1000 x 1000 ppi image from the same file. The same image needs a different amount of sharpening for viewing on a screen or the Web and different for different printers (laser lab print versus inkjet printer with dithering).

I often find that fixing the contrast from a Raw file greatly reduces the amount of sharpening that is needed as these are very similar processes in terms of how they process the image data.