Sharpening in Photoshop  

When you take a picture, you want it primarily to have a good contrast. If you look at two images put together, each of them having a different level of contrast applied, most of the times the one with the richer contrast will appear more appealing to the observer.

If you have used Adobe Photoshop before, you might have used the Unsharp Mask filter. In many cases using this filter will give your pictures a cleaner look; it will appear as being more focused and have more details. Also, if you have applied other filters on that image, you might have ended with a softer picture. However, using the unsharp mask filter is not always recommended, as in the case of large or already noisy images, it will lead to unsatisfactory results.

Many people have heard the adding some sharpening in Photoshop might produce better looking images and they modify the values in the filter’s option control without knowing many things about what they are doing.

Sometimes sharpening is required because of the limitations of the camera which the picture was taken with. The digital systems in modern cameras, no matter how sophisticated they are, cannot capture the infinite number of colors available in nature. Also, fine detail, usually the elements smaller than the pixel size will not appear in the final image. Another problem occurs with diagonal lines, mostly when they have a distinct color from the background. Most cameras use an anti-alias filter to blur the differences of pixel color from one part of the image to another in order to avoid the stair-step artifacts. When looking at such a picture, your brain will perceive those more blurry lines as being out of focus or lacking sharpness.

You may want control more closely the amount of sharpening you perform on a picture and that is where the multiple modifiable options of the Unsharpen Mask Tool come into play (Amount, Radius and Threshold). By adjusting the Amount setting you choose the sharpening action’s aggressiveness. The Radius setting controls how wide an area at the transition is affected. By modifying the Threshold option, you chose how much difference there will be between two adjacent pixels before any change is made.

When looking at a picture depicting either a person’s portrait or a nature shot, you do not want to see the annoying sharpening artifacts which can affect a large block of color. If large areas of the picture are exaggeratedly sharpen, any noise preset in the image, but otherwise not so visible, will show up and make the image look grainy. You may also want to consider that a sky or a skin tone having way to much detail don’t seem that natural as more degraded ones. In a portrait picture, the bokeh (the character of out-of-focus areas) is more appealing when it does not contain annoying digital noise or extremely sharpen details.

Below there are a series of easy to follow steps which will help you in understanding and learning to work with the edge sharpening in Photoshop. To easily understand the purpose of this tutorial, what you essentially do is to build a mask of just the edges in your image. After that you will apply sharpening to the areas under the mask.

Start the Adobe Photoshop and import the image you want to modify (do this by selecting File > Open).

Before starting any modifications to the sharpening level of the selected picture, be sure to do all the other changes to it (such as color correction, changes to the saturation, distortion corrections, etc). Adjusting the sharpness of the picture should be the final element you change at your image.