What's new

Unsharp Mask


Lee

Guru
Messages
552
Likes
0
In the Unsharp Mask tool there is an option to just Sharpen Edges. Just out of curiosity, when would you want that option as opposed to just the sharpening the entire image?

Also, I found out about a new selection tool by accident. Was watching Tech TV and they had a photoshop guy on there explaining "stuff." He did a little demo on the Color Range tool. I'd never even noticed it. Boy is THAT thing cool!!! It is so precise compared to the Magic Wand etc. You want a specific color selected (like a red car) that tool gets it without touching anything else including all the different shades of the red within the vehicle.

I wonder HOW MANY other tools in PS I have not even noticed that do great things. Probably plenty. :D
 

Rantin Al

Guru
Messages
566
Likes
0
Hi Lee, Suppose you had a skyline or horizon with buildings with windows,frames etc. You may want to sharpen the sky edge and windows, but not the textures of the buildings. this is one reason for the option.

Try this for sharpening, instead of the USM.

Duplicate the layer needing sharpened.
Run the Filter > High Pass > experiment with radius settings.
You will see the edges, almost like the Emboss filter, against a mid-grey.
Set the Blending to Hard Light and adjust the Opacity.
Experiment with the other Blending 'Light' modes.

I use the Colour Range selection as my weapon of choice for masking.
As you say it gives greater control than the Magic Wand ever could.

Keep exploring, there's tons more for you to discover. ;)

Cheers Al[/b]
 
G

Guest

Guest
Lee, in some cases when use the Color Range tool, it's advisable to use some feather (Select/Feather). A value of 1,2 or 3 will do in most cases (depends also on the resolution of your document). It makes the transition from the selected area to the area surrounding it a bit smoother.
 

Erik

Guru
Messages
1,534
Likes
2
another use of sharpening only the edges is when you're stuck with one of them ugly jpg files. Applying unsharp mask will then bring out the jpg structure even more clearly. (you'll start seeing squares etc). When using an edge mask, you can avoid this.
My method is to go to LAB mode, make some edge mask in the lightness channel and apply sharpening the greeyscale without messing up the colour info.

Don't forget that Unsharp Mask is nothing but a kind of algorhythm that compares pixel-values and if the diff is more that a certain value, makes it even more. Thios means that colours will definately change, hence those ugly sharpened images. Use greyscale and most of your probs are solved.

There have been several threads on edge masks, just do some search.
 

wbiss

Guru
Messages
2,313
Likes
7
Great info here guys! :perfect: :D Thanks for sharing!

R.A. I really like your method of 'sharpening'! :perfect:
 

Rantin Al

Guru
Messages
566
Likes
0
Thanks Wendy, but it's not really mine. ;\ I'm just spreading the goods. ;)

Al
 

tranquil222

Power User
Messages
230
Likes
0
Caveat about Color Range

Color Range selects a set of pixels of like color just like the wand but the difference between color range and the magic wand is that color range can and will select some pixels partially(meaning there will be transparency if you are to move the selection), whereas the magic wand selects pixels completely. Using color range can be a pain if you're trying to extract an element from an image, and it gives you less control over any adjustments that you want to apply. Color range does have its place in the toolbox, however, the magic wand is better overall.
 

Rantin Al

Guru
Messages
566
Likes
0
T222, I should have explained the way I use the Colour Range selection a bit further.

Make the colour range sample to give the maximum outline of the object.
Then take the selection straight into a mask and tidy it up.
Add a bit of Gaussian Blur, the amount depends on the image resolution.
Use the Levels grey slider to choke in/ choke out.
Use the Levels Black & White sliders to tighten the edge.

This gives a lot more control than available using the Magic Wand.
Neither is better or worse, each has it's place. It's just one technique which I find gives good, quick results.

Cheers Al
 

wbiss

Guru
Messages
2,313
Likes
7
Thanks... I very much appreciate your explanation R.A.! ;)
 

Top