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Sharpen+ (Advanced Unsharp Mask) v3.1 (2008-12-24)

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I prefer to sharpen my photos with unsharp mask, because of finer results compared to built-in sharpen effect. So far I had to use other programs for that operation. Switching between programs is annoying - so I decided to learn the code and design a plugin with features I need. Hope you find it useful too.


Menu location: Effects > Photo.

Download as part of my plugin pack.




Updated to version 3.1 (2008-12-24)!

Changes: few UI and code optimizations.


Updated to version 3 (2008-08-31)!

Changes: Threshold control is re-designed to have much better feel and control over the result. Previous threshold had strong impact already from very small values, while large values were quite useless. The new one is literally "zoomed in" to small values only, so it is easy to find good setting with scrollbar.


Updated to version 2 (2008-01-03)!


- re-located the effect into Photo submenu

- added Review button (press & hold the button to see original image, release it to see changes)

- improved keyboard usability

- reduced default Radius to 1 which is more suitable for most of images, especially for screen size photos

- Color Mask has now some real impact on results: by aming strength based on pixel color. Range is expanded to 0-200

- Tonal Range control in Highlights tab is reversed, in order to work in same direction as in Shadows tab: increasing the value expands the range

- Faster rendering after OK click, especially when image fits to window

- Code optimized for Paint.NET 3.2 (though it's still not a PropertyBasedEffect)

- Source code available (VS2005 express):


Using the plugin:

* use three main controls (on top) to achieve required effect

* use adjustment controls (in tabs) to fine-tune the result

* re-adjust any control if needed


Main controls

Those are traditional unsharp masking controls (learn more here):


Amount - percentage of sharpening to be applied

100 - 200 usually does the job.


Radius - width of area (pixels) around edges to be sharpened

1 is good for small (web) images; 2 - 3 for large (several MP) images.


Threshold - minimum level of pixel contrast (brightness difference between pixels) to be sharpened

Use it to prevent sharpening of even surfaces like sky or skin. Keep at zero if you want to sharpen fine details.


Adjustment controls

those naturally don't apply any additional effect, but rather adjust it's strength by percentage from main Amount:


Edge Balance

Bright Borders - Percent of amount applied to bright side of edge

Use it to reduce sharpening halo if it becomes too visible, or prevent oversharpening of bright fine detail, like sunlit hair.

Dark Borders - Percent of amount applied to dark side of edge

Use this to reduce dark halo (rarely needed).


Note: it is not recommended to use Bright and Dark controls together: it would effectively reduce overall amount of sharpening (setting both to 0 is equal to setting main amount to 0).



Strength - percent of amount applied in shadows

Use it to reduce sharpening impact to image noise (noise is usually most pronounced in shadows).

Tonal Range - level of brightness (at 0 - 255 scale) where shadows adjustment will be applied

Range is "soft" control: strength of sharpening rises gradually back to normal through 50 next levels above selected level.

Tip: set Strength to 0, move around Range control to find the brightness level where noise kicks in, then re-adjust Strength to appropriate amount.



Strength - percent of amount applied in highlights

Tonal Range - level of brightness (at top of 0 - 255 scale) where highlights adjustment will be applied

Range is "soft" control: strength of sharpening rises gradually back to normal through 50 next levels below selected level.


Color mask

Adjusts strength of effect based on pixel color



* Strength of controls is NOT equal to "other brand" sharpening tools (like USM in Photoshop or Gimp). For example radius 2 in this plugin is close to radius 1 in Gimp USM (due to differences in Gaussian blur rendering). So don't apply settings recommended in Photoshop tutorials - better trust your own eyes.

* Sharpness (edge contrast) is increased through brightness channel only - thus no hue shift is caused (as far as color channels are not clipped); this is another difference from "other brand" USM tools.

* Shadow and highlight areas are detected from blurred grayscale image, to achieve more even output spread.


Alternative use:

Instead of sharpening you can use this plugin for local contrast enhancement - to give extra clarity to a flat, hazy image;

for example following settings: Amount 20, Radius 80, Threshold 0.

(Be patient with this one: the larger the radius, the slower the effect runs - due to Gaussian blur function rendered in background).



General recommendations for sharpening (collection of unwritten rules I try to follow)

* Sharpening only works on sharp images. Use it to remove lens softness or give 3d look to otherwise flat image.

* Don't try to fix blurry images with sharpening - it only makes things worse. Leave it blurry or shoot the photo again.

* Sharpening should be the very last image processing operation before save / print, as it actually distorts image detail for better appearance

(Generally my preferred workflow is: white balance -> noise reduction -> levels/curves/contrast -> saturation -> crop/resize -> sharpening).

* The best sharpening settings depends on output - whether it is web image, small print or large print - every kind has different needs. Do experiments to find most appropriate settings.

* For best output preview (to predict the results), use 100% zoom while sharpening a web image, use 50% zoom if sharpening for print.

* Images appear sharper on LCD monitors than CRTs. So be careful while using CRT.

* Mass production printers at photo stores automatically sharpen every jpg image (while they may keep tif's intact). So keep your settings modest or don't sharpen at all if you are going to use those services.


Edited by toe_head2001
Restored image

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This is impressive! :shock:

I really like the UI, it's easy to understand and work with.

Rick, I definitely suggest that you consider including this in a later version!!

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Wow. I have to use some time to figure out all those controls. But this really dose the job very well.

Thank you for making this plug-in.

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This is simply a must use!

The fine-tuning your plugin has is outstanding! It's all about the details.

As moc426 stated: ...impressive!

Thank you much!

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This looks really nice. It will take me a litte bit to get to know how to use everything in it really good though. Still, I can see this as becoming very useful. Great job!

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...Most impressive. :-)

I like it a lot. Keep 'em coming!

That was vader's line, not palpatine's...followed by "...Obi-Wan has taught you well. But you are not a jedi yet..." (my little brother watched the original trilogy once a day for about 3 months...thank god it takes some time to rewind VHS tapes).

I'm getting some interesting results using this on gradients at very high values...this might turn out to be even more interesting for stuff it's not even meant to do :)

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Fixed. I'd completely's been way too long.

I am slightly overwhelmed with this huge range in the UI. Any chance a highly-motivated individual could post an explanation of what each does?

AHA. EDIT: Nevermind. I just saw the post I had ignored.

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Thanks to everyone for positive feedback :)


You totally ripped off the "+"!



hehe, I'll try to compensate it somehow... say, with some more plugins?

Actually there's a good reason for the "+" extension, it places the plugin nicely next to the original Sharpen in the effects menu.

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