Sharpening

[T Paul]

(from Steve A.K.A Trimoon )

1. Copy your image and name the new layer sharp 1

2. Go to Filter>Sharpen>Unsharp Mask

Settings: Amount 200, Radius 8, and Threshold 4. Note, this should greatly over sharpen your image but the next step will resolve this.

3. Next duplicate this layer and name the new layer sharp 2.
Set the blending mode for this layer to LIGHTEN, set the layer mode on sharp 1 to darken.

Experiment with the opacity modes for both layers until you are satisfied with the results.

By adjusting these two layers you will sharpen the image and do away with the edge effect caused by the overuse of the Unsharp Mask filter. It doesn’t work with every image, but 80% of the time it does.

[T Paul]

High Pass Filter Sharpening - Optional Layer Mask

Filter turns all non-edge areas to neutral gray but leaves edge intact. This technique is used in combination with the Soft Light or Overlay Blend modes.

1. Duplicate image.

2. Apply the Filter/ Other/ High Pass filter with radius settings of 3-6. Low-frequency images -- those with close subjects and soft detail -- generally require a higher Radius setting than high-frequency images with lots of fine detail.

3. Change the blend mode to Overlay. The neutral tones in the image are eliminated and the edges accentuated. Use the Opacity slider to control the effect. Use Soft Light blend mode for a softer effect. Overlay produces a little more contrast.

4. Add a layer mask (Option/Alt layer mask button at bottom of Layer palette) on duplicated layer with Reveal All to paint back in original image smoothness, or Hide All to paint in sharpness in selected areas.

5. Stack multiple sharpening layers with layer masks to adjust different areas of an image.

[T Paul]

(from Steve A.K.A Trimoon )

1. Copy your image and name the new layer High Pass

2. Go to Filter>Other>High Pass, now the following settings are not set in stone, you can play with them for different results, but for this we’ll use the following. Let’s try a radius of 10. Then set your blending mode for this layer to overlay. Using the Opacity, adjust accordingly.

Sometimes I will create a couple of layer like above, but different adjustments. By turning each layer off & on you see which one gives you the best results for this particular image. I also will adjust for a certain area, say the eyes; and will mask out the rest and delete, which will give you sharp eyes, yet a soft look to the rest of the image. Again using the Opacity adjustment for just the right look.

This above method of using the high pass filter is something that I used a year or so ago and no longer recommend this method except for certain special effects when doing artistic renderings. Below is a link to the method that I now use, which uses the custom filter. I think you will find it a much better way of doing things. It applies a slight blur to the image before sharpening. After a while, you get to where you are so good at it that you do it intuitively.

Better Than USM

[T Paul]

Books

Adobe Photoshop 7 Advanced Digital Imaging by Against the Clock

Photoshop 7 Wow! Book by Linnea Dayton & Jack Davis

Photoshop Restoration & Retouching (2nd Ed.) by Katrin Eismann

"Out of Gamut: What You Always Wanted to Know About Sharpening But Where Afraid to Ask", two internet tutorials by Bruce Fraser

Photo Re-touch Secrets by Scott Kelby

The Photoshop book for digital photographers by Scott Kelby

Good RetouchPro Threads:

Smart Sharpening

Sharpening using Photoshop (Something Different)

Sharper Images

Good Links:

Understanding Digital Unsharp Mask

Sharpening and USM

Sharpening Techniques

Photoshop High Pass Filter

Everything You wanted to Know about Sharpening

Tutorials

Smart Sharpening Tutorial

Bruce Fraser Two Pass

Glenn Mitchell tutorial on sharpening

Advance Sharpening Movie by Russel Brown

Better than USM

[Mosha]

Are you a teacher...?

Thanks for this wonderful explanation.
Taking advantage on your knowledge... can you do the same thing but for channels...I just don't get them. The more I try to understand them, the more I get confused...

Congratulations

Mosha

[T Paul]

Not a teacher, but I am self-taught so I am pretty good at searching the web or my books for information. As you can see from my resources I gathered this information from all over the net. I find it nice to have all the information at your fingertips.

I'll add channels to my list of things to do.

~T

[Mosha]

What can I say....just... THANKS...

[W. Rose]

Great Job T. Paul,
This has really helped me alot.

[T Paul]

Glad to hear that this is helpful!

If anyone else has a sharpening technique or favorite USM setting I didn't include, please feel free to add them.

[byRo]

Originally Posted by T Paul

(from Steve A.K.A Trimoon )
This above method of using the high pass filter is something that I used a year or so ago and no longer recommend this method except for certain special effects when doing artistic renderings.
..........
Better Than USM

I saw this yesterday in the other thread ('something different') and went running to the link. I was planning to spend the weekend (wife permitting) immersed in convolutions and filter factories.

But..
Can anybody give us a jump start on the learning curve?
Is it better than USM? If so, when and how?
Is it better than high-pass? If so ,when and how?
Use custom filter, or filter factory, or something else?
etc??

Roland

[T Paul]

Excellent question, but one I can't answer. Perhaps someone else will be able to.

Here is a quick low down on the three filters:

From the PhotoShop help file:

Custom Filter

Lets you design your own filter effect. With the Custom filter, you can change the brightness values of each pixel in the image according to a predefined mathematical operation known as convolution. Each pixel is reassigned a value based on the values of surrounding pixels. This operation is similar to the Add and Subtract calculations for channels.

You can save the custom filters you create and use them with other Photoshop images.

To create a Custom filter:

Choose Filter > Other > Custom.
Select the center text box, which represents the pixel being evaluated. Enter the value by which you want to multiply that pixel's brightness value, from -999 to +999.

Select a text box representing an adjacent pixel. Enter the value by which you want the pixel in this position multiplied.

For example, to multiply the brightness value of the pixel to the immediate right of the current pixel by 2, enter 2 in the text box to the immediate right of the center text box.

Repeat steps 2 and 3 for all pixels to include in the operation. You don't have to enter values in all the text boxes.

For Scale, enter the value by which to divide the sum of the brightness values of the pixels included in the calculation.

For Offset, enter the value to be added to the result of the scale calculation.
Click OK. The custom filter is applied to each pixel in the image, one at a time.

Use the Save and Load buttons to save and reuse custom filters.

High Pass

Retains edge details in the specified radius where sharp color transitions occur and suppresses the rest of the image. (A radius of 0.1 pixel keeps only edge pixels.) The filter removes low-frequency detail in an image and has an effect opposite to that of the Gaussian Blur filter.

It is helpful to apply the High Pass filter to a continuous-tone image before using the Threshold command or converting the image to Bitmap mode. The filter is useful for extracting line art and large black-and-white areas from scanned images.

Unsharp Mask
The Unsharp Mask does not detect edges in an image. Instead, it locates pixels that differ in value from surrounding pixels by the threshold you specify and increases the pixels' contrast by the amount you specify. So, for neighboring pixels specified by the threshold, the lighter pixels get even lighter and the darker pixels get even darker based on the specified amount.

In addition, you specify the radius of the region to which each pixel is compared. The greater the radius, the larger the edge effects.

A while back there was a discussion on the Custom Filter in this thread

Also here are some web links that may be helpful if you want to tackle convolutions

Convolution Web Links
Creating Custom Filters Photoshop Tutorial

Convolution Corner

Convolution Kernels

Custom Image Filter

Home-made effects: Creating your own filters - lots of info here

[kbeatrice]

Hi T. Paul, this is a great summary of sharpening methods! In the layer mask section I think that you might have accidentally swapped the brush colors:

Next add a layer mask by Option/Alt clicking the mask button at the bottom of the Layer palette. This creates a Hide All (black) mask. Use a large, soft, black airbrush on the mask to show the sharpening where you want it.

Or: create a Reveal All (white) mask by simply clicking the mask button at the bottom of the Layer palette. Using a white brush will HIDE the sharpening effect where you paint.

Did you mean white airbrush on black for the first one and black brush on white for the second one?

Thanks again for the great summary!

[byRo]

Originally Posted by T Paul

Also here are some web links that may be helpful if you want to tackle convolutions..........

Wow, who needs Google when T Paul's around!

Didn't find much in the way of answers, did find a whole bunch of questions....
Seems like I'm going to be pretty bleary-eyed come Monday.

thanks,

Roland

[T Paul]

Originally Posted by kbeatrice

Hi T. Paul, this is a great summary of sharpening methods! In the layer mask section I think that you might have accidentally swapped the brush colors:

Ooops! Thanks for catching that. That post has been corrected.

[T Paul]

Originally Posted by byRo

Wow, who needs Google when T Paul's around!

Didn't find much in the way of answers, did find a whole bunch of questions....
Seems like I'm going to be pretty bleary-eyed come Monday.

thanks,

Roland

Yes the whole convolution thing is rather confusing. I think the best plan is to use some of the examples and start experimenting on your own.