Sharpen vs unsharp mask vs ACR sharpen

Years ago I learned this Technique from Deke McCelland, and it works very well for me

1- Duplicate the Layer, and make sure you are viewing your Image at 100%

2- Filter-Sharpen-Unsharp Mask. Radius less than 1.0 Threshold: 0, play with the Amount.

3- Edit-Fade Unsharp Mask Opacity: 80%. and set the Mode To: Luminosity.

4- Add A Layer Mask to the Layer

5- Select your Brush Tool , and with Black Color set to your Foreground Color, Brush the areas that you don't want to be sharpen.

and If you want to change the Mask area for sharpen, With White Color set to your Foreground apply Mask to the areas, that you want to be Sharpen.

6- Layer-Flatten Image

If you are curious about the seeming contradiction  -- unsharp masking actually sharpens an image – this may help. It is part of an introduction to the subject that I wrote for my students:

***

The term “Unsharp Mask” in Photoshop is derived from a graphic arts photographic color separation procedure. In essence, Photoshop’s Unsharp Mask imitates the sharpening portion of a dual-purpose film mask.

Commercial Printing (Prior to the use of computers):

Normally, one of the first objectives when color separating a color transparency (a “chrome”) using a camera and photographic film so that printing plates may be made, is to reduce the density range of the chrome so that it fits more easily within the more limited tone gamut of halftone reproduction.

To achieve this, a low contrast negative is made -- using black & white film -- by contact exposure to the transparency (which is a positive). Next, the two films – the positive transparency and the low contrast negative black & white film image -- are sandwiched together. The negative film reduces the density difference between highlight and shadow extremes of the image to be photographed during subsequent color separation and halftone steps. So much for range and contrast reduction alone.

If, instead of placing the black & white masking film in direct contact with the chrome during the making of the negative, a sheet of diffusion material (a special frosted plastic) is placed between chrome and film, the resulting negative lacks knife-edge image sharpness. Instead, the film – the black & white film negative mask -- takes on a soft-edged, out-of-focus look. When this mask is then placed in contact with the chrome for color separation, it performs two functions.

First, since a low contrast negative (the mask) is sandwiched with the positive (the chrome), overall range is reduced. Second, at the points of sharp edge contrast in the original transparency, contrast is increased, as shown in the illustration, giving the impression of a sharper image.

Obviously, if the transparency is not sharp to begin with, there will be no clearly defined edge-contrast to accentuate. An unsharp mask cannot rescue a blurred, soft-focus image.

As mentioned at the outset, Photoshop has adopted the term Unsharp Mask and its controlled use because it mimics the image sharpening portion of photographic masking procedures. Where, during the making of photographic masks, variations in the amount of sharpening are created by altering film exposure time, its development time and/or the number and thickness of the diffusion sheets, Photoshop offers similar controls in the Unsharp Mask dialog box.

When Filter > Sharpen > Unsharp Mask is chosen, three controls are offered.

Threshold level determines at what point the sharpening will kick in. The higher the number, the greater must be the difference in density of adjacent tones in the original image before the unsharp mask is activated.

Radius denotes the width of the sharpening effect.

Amount governs the degree of change; the amount that the light edge is made lighter and the adjacent dark edge made darker (see the illustration above).

One final reminder: Sharpening, one of the last correction operations, should be done at 50% or 100% of image size.

hhost05  wrote And then, once you've brought it into Photoshop, there's 3 additional ways: (1) unsharp mask, (2) sharpen, and (3) smart sharpen

The reason there are so many sharpening options is that they were added over time. In Photoshop, the problem with Sharpen is that there are no options, so if you don't like the result there's not much you can do about it, so Sharpen is usually ignored.

Unsharp Mask has three useful options, so it is widely used by professionals. But it has its flaws too, including: It sharpens everything equally, so as you increase sharpening to bring out details, noise in flat areas like skies may become more visible. It can result in color fringing because it sharpens all the color channels. Pros get around those problems with various workarounds like the High Pass mask technique or applying Unsharp Mask to the image luminance and not the color.

Smart Sharpen came later and was designed to get around those problems. If used correctly, it can protect smooth areas and highlights and shadows so that you can turn up the sharpening much further before the image starts to fall apart. It sharpens tone much more than color so that you can avoid color fringing. On many images, you can apply Smart Sharpen and not have to do anything else.

Camera Raw sharpening also came later and was designed for intelligent sharpening, but to raw files. It has a Masking slider so you may not have to use masked High Pass sharpening later, and like Smart Sharpen, it's designed to sharpen without creating the problems you get from Sharpen and Unsharp Mask.

hhost05  wrote Is sharpening in raw preferable? I shoot landscapes mostly.

Different kinds of sharpening should be applied at different stages of your workflow. Others have already mentioned capture sharpening and output sharpening, but there's also creative sharpening. Generally, apply capture sharpening in Camera Raw, apply creative sharpening in Camera Raw or Photoshop, and apply output sharpening from whatever application is creating the final print or web image (for example, the Output Sharpening option in the Save dialog box of Camera Raw).

The notion of capture/creative/output sharpening was introduced by the late Photoshop expert Bruce Fraser (read his 2003 article Thoughts on a Sharpening Workflow), and it's valuable to learn because current Adobe sharpening philosophy is built around his ideas. You can go deeper into it by reading his book Real World Sharpening.

The sharpening you do in Camera Raw is called Capture sharpening, and is designed to compensate for loss of sharpness in the digital capture. It does a very good job, and I recommend that you use it. The image should look sharp, but not too sharp. If in doubt, sharpen less. It is very important to apply and evaluate sharpening at 100% view, any other view will be inaccurate and misleading because of image scaling.

If you click the underlined text at the bottom of the Camera Raw window (Workflow options) you can set Output sharpening for screen or print. (designed to compensate for loss of sharpness when resizing and/or printing the image) Try using Medium sharpening.

I use output sharpening for screen, but not for print - I find it too harsh, and use Smart Sharpen for sharpening for print.

I haven't used Unsharp mask for many years - Camera Raw/Smart Sharpen is in my opinion much better.

(I use Lightroom and not Camera Raw, but the capture sharpening and output sharpening are exactly the same)

A handy little extra step that I use on occasion (it depends on the image content and its end use) is to add a composite layer and do your sharpening there. It allows you to add a mask and either reduce or eliminate local sharpening that may be overdone and/or a distraction.

You can also use a highpass filter to sharpen.   What will sharpen best may depend on the image's contents and the intended use of the image sharpened. Many prefer to sharpen at sever points in time and to do a final output sharpening for the image intended use. print or web or publishing, etc.  A billboard does not need to be as sharp as a wallet size print.  Different sharpening can introduce sharpening effects like the jaggies.