Sharpening is the tool that everyone seems familiar with – at least to a degree. We looked at the noise reduction techniques earlier in this course and now it’s the time to consider how to maximise the look of the final image. Today I am looking at how to achieve the best results from sharpening for print.
For this exercise I am using a portrait image. I first open it in Photoshop and after a slight tonal adjustment; I am ready to start working on sharpening.
There are many tools in Photoshop that would allow to perform some sharpening adjustments. It is important to remember that some sharpening can be done with Camera Raw and Adobe Lightroom. However, we are now at the final stage of the process and, as we are getting ready to print out the final image, the sharpening adjustments might be quite specific and distinct from the noise reduction techniques used at the beginning of the digital workflow.
To start my exercise, I am going to open the file in Photoshop and go straight to Filter – Sharpen – Unsharp Mask. The Sharpen section contains more than one tool; these tools are: Sharpen; Sharpen More; Sharpen Edges; Smart Sharpen, and Unsharp Mask. My usual preference is to use the Unsharp Mask tool. It seems to offer a wider range of controls than the first three tools mentioned here. Smart Sharpen filter has two modes: basic and advanced. The Advanced mode is useful, for example, when there is a need to sharpen the shadow and highlight detail differently. However, there are similarities between the Unsharp Mask and the Smart Sharpen filter. The latter also is likely to work slower so I usually prefer to use the Unsharp Mask.
Picture 1: Unsharp Mask controls
There are three main controls in the Unsharp Mask tool: Amount; Radius, and Threshold.
The Amount slider regulates the volume of the adjustment so increasing it would increase the overall amount of sharpening. Below is the demonstration of this slider on the maximum setting (at 500%).
Picture 2: The image with Amount set to the maximum level
The radius slider on its own does not always lead to noticeable changes – this is because it regulates the width of halos around the edges in the image. It works best in combination with the amount and threshold adjustments. Generally, the small radius would make more difference in the fine details of an image rather than anywhere around broad and wide areas and edges.
The threshold shows the level of values at which the filter starts applying the sharpening function to the edges. This setting is important, for example, in portraits to make sure that the smooth areas of the skin won’t become speckled. The image below demonstrates the importance of setting the threshold!
