# Sharpen vs. Unsharp Mask



## AprilEye (Feb 17, 2011)

Can someone explain to me the difference and benefits of adjusting Sharpness vs.  Unsharp Mask?  I have the forum but am still confused.   Thanks Peeps!


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## DerekSalem (Feb 17, 2011)

Read this link

Too hard to explain technically...but usually better to use Unsharp mask.


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## GooniesNeverSayDie11 (Feb 18, 2011)

Unsharp mask is typically the preferred method and is derived from film darkroom techniques. I believe they would use a slight OOF/blurred (unsharp if you will ) copy overlayed ( masked ) on a normal copy, so the blurred lines would fatten or sharpen the already somewhat crisp lines. That explains the seemingly contradictive name. Atleast its something along those lines, I may be slightly off. As for differences, do a google search. It turned up a ton of pages with explainations.


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## subscuck (Feb 18, 2011)

While I wouldn't say Unsharp Mask is the preferred method, I would say it's all you need if focus was dead on SOOC, and your pic is softened a little after resizing, color correcting, etc. Smart Sharpen (I assume we're talking PS here) is more of a "big gun" approach. It uses more complex algorithms and has more user controlled options for sharpening, like correcting for lens blur or motion blur, etc. I use Smart Sharpening when I've missed focus by a little bit, and quite often it can save the pic where Unsharp Mask can't. There are limits, of course. Then you start getting into the world of Lab sharpening, Luminosity sharpening... Understanding and using sharpening is it's own discipline within editing.


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## SlickSalmon (Feb 18, 2011)

I have read both sides of the argument from equally authoritative sources.  One says that "Sharpness" is "Unsharp Mask" without a threshold slider; the other says that "Sharpness" uses advanced algorithms that render the threshold slider unnecessary, and that PS keeps it around for the old folks.  I'm an old folk, so I use "Unsharp Mask".


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## KmH (Feb 18, 2011)

AprilEye said:


> Can someone explain to me the difference and benefits of adjusting Sharpness vs. Unsharp Mask? I have the forum but am still confused.  Thanks Peeps!


It depends how much, and what kind of noise the photo has. Noise reduction needs to be assessed and performed before you can consider sharpening. *Note*: In the Sharpness dialog box there should be a "Learn More About: Adjust Sharpness" link you can click on for more information.

The goal when sharpening is to control the contrast of any edges in the photo. More specifically, the goal of sharpening is to control edge halos.

A portrait has far fewer edges than a tree filled landscape has. The portrait is a low frequency image and requires a larger radius setting while the 
landscape is a high frequency image and requires a low radius setting.

As mentioned the details get fairly technical so you may want to get the book: Real World Image Sharpening with Adobe Photoshop, Camera Raw, and Lightroom (2nd Edition)


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## KmH (Feb 18, 2011)

GooniesNeverSayDie11 said:


> Unsharp mask is typically the preferred method and is derived from film darkroom techniques. I believe they would use a slight OOF/blurred (unsharp if you will ) copy overlayed ( masked ) on a normal copy, so the blurred lines would fatten or sharpen the already somewhat crisp lines. That explains the seemingly contradictive name. Atleast its something along those lines, I may be slightly off. As for differences, do a google search. It turned up a ton of pages with explainations.


The way unsharp masking is done in a darkroom is two identical negatives, and a small plate of glass are used.

One negative is placed on one side of the glass, and the second negative is registerd over the first negative but on the opposite side.

The glass plate is then placed in the enlarger and is focsed on the bottom negative. That makes the top negative slightly out-of-focus. The amount of unsharp masking is controlled by the thickness of the glass plate.
It was/is a huge PITA technique to use.


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