Sharpening

©Doug Weldon Photography - www.dougweldon.com 

<< Previous | Tutorial Index | Next >>



 

Just as with noise reduction, there are sharpening plugins available for Photoshop. However, with a little bit of care, Photoshop's sharpening tools are just as good, and they do not require any additional purchase. Although, I must say that my recent experiences using Nik Software's Sharpener Pro in preparing prints for sale has been excellent and that I am beginning to become more reliant on it.

 

You will notice that, as with noise reduction, we are not using a layer to sharpen our sample image. We are working directly on the image's pixels. We can use a layer to sharpen, but it is a bit more complicated to do so. We will reserve layer-based sharpening for the advanced sections of the tutorials. 

 

Sharpening is another adjustment that can easily be overdone. Realize that sharpening cannot make poorly focused images sharp. You must record the sharpest image possible at the time of capture if you want crisp, clean images.

 

So then, if I have a good critically focused capture, why do I need to sharpen at all? 

 

The conversion process, the adjustments we make to the image, and perhaps most importantly, the anti-aliasing filter over the sensor in many digital cameras, contribute to some innate softness in digital images. If you are shooting JPEG, the likelihood is that your camera's software does some sharpening for you as the image is processed for saving on the memory card. If you are shooting RAW, all of the processing is left to you. Either way, most, if not all, images benefit from some sharpening. 

 

In fact, your intended use of the image will impact the degree of sharpening that you apply. Images destined for screen display generally do not need as much sharpening as images that will be printed. More on that later.

 

If you would like a good primer on the technical side of the sharpening discussion, you can find one here - http://www.bythom.com/sharpening.htm

 

The tool that is the most widely used in Photoshop to sharpen images is the Unsharp Mask. It can be accessed from the Filter Menu.

sharpen

When selected, you get the Sharpening Dialogue.

sharpen2

We will concern ourselves with the first two controls in this dialogue - Amount and Radius.

Let's take a look at a sample image.

sharpenimage

The original capture was fairly sharp, but there is a lack of real crispness in the peeling paint on the doors and the flower pots on the balcony. Let's take a closer look.

sharpenimage3

 Now let's look at a slightly over-sharpened sample for purposes of illustration. 

sharpenimage4

 As you can see, more detail is revealed after sharpening. Now let's take a look at an image that has been obviously over-sharpened . You can see "haloing" effects clearly here. The image begins to look artificial. This is especially apparent around the railing and on the wall. 

sharpenimage5

 It is recommended here that our two controls of concern, Amount and Radius, be set as follows:

 

Radius should be kept at somewhere around .5. From time to time it will be necessary to increase Radius to achieve desired effect, but rarely is it necessary to exceed 1.0. That is not to say that there are some situations under which Radius will have to be a bit higher. Critical judgment is necessary here. 

 

Amount will vary. At a Radius of .5, I usually start at about 200 and test different Amounts. You can preview the effect of your settings by checking the Preview box just under the OK and Cancel buttons.

 sharpen2

You can see that, for this sample image, I have used a Radius of 1.0 and an Amount of 206. Again, we have a subjective judgment that needs to be made here. The novice usually tends to over-sharpen. If artifacts become noticeable in your image, you have over-sharpened.

 

You will notice, however, that slight over-sharpening when you intend to print seems to improve your printed images. You will have to experiment to see just how much over-sharpening will work for your printer/ink/paper combination. Of course, the assumption here is that you have calibrated your monitor and adhere to a color management routine in preparing images for print. 

 

Special Note: Since developing this tutorial, I have moved over to using NIK Sharpener Pro 3.0.  The principles of sharpening remain the same, however. 

 


<< Previous | Tutorial Index | Next >>