Adobe Photoshop CS5 for Photographers - Martin Evening [120]
2.
A high radius setting will over-emphasize the fine edges, but do more to enhance the soft edges, such as the facial features in a portrait. I have shown here the two extremes that can be used, but for most sharpening adjustments you will want to stick close to a 1.0 Radius and make small adjustments around this setting.
The suppression controls
The Amount and Radius sliders are used to create the sharpening effect, while the next two sliders act as ‘suppression’ controls. These can be used to constrain the sharpening and target the sharpening effect where it is most needed.
Detail slider settings
Where I describe the Detail panel as acting like a suppression control, it is important to understand that when the Detail slider is set to 100, this matches the old Camera Raw sharpening where no additional edge halo suppression was employed. Any setting that is less than 100 effectively suppresses the Camera Raw sharpening. Therefore a low Detail setting has a maximum effect and a high Detail setting has a minimum effect.
Detail slider
The Detail slider suppresses the halo effects in the image. It allows you to increase the Amount sharpening but without generating too noticeable halo edges in the image. There has always been a certain amount of halo suppression built into the Camera Raw sharpening, but you can now use the Detail slider to fine-tune the Amount and Radius effects by setting Detail to a low value. One of the minor changes in the new Camera Raw 6.0 sharpening means that higher Detail slider settings are more likely to exaggerate the highest possible edge detail in the image. This can result in the Lightroom sharpening emphasizing any areas that contain fine- textured detail (and noise). As a result of this you may want to avoid setting the Detail too high if this is likely to cause problems. Another option is to increase the Masking setting.
1.
In this first example the Detail slider is at the default setting of 25 and captured here with the key held down. This displays an isolated grayscale preview of the sharpening effect. At this setting the Detail slider gently suppresses the halo effects to produce a strong image sharpening effect, but without over-emphasizing the fine detail or noisy areas of the image.
2.
If you take the Detail slider all the way up to 100, the capture sharpening will be almost identical to a standard unsharp mask filter effect applied in Photoshop at a zero Threshold setting.
3.
If, on the other hand, you take the Detail slider down to zero you can see how the image looks with maximum halo suppression. What we learn from this is how to set the Detail slider between these two extremes. For portraits and other subjects that have soft edges, I would recommend a lowish Detail setting of around 20-30 so that you prevent the flat tone areas from becoming too noisy. For images that have lots of fine detail I would mostly suggest using a higher value of 30-50, because you don't want to suppress the halo edges quite so much. With these types of photos you probably will want to add more emphasis to the fine edges.
Interpreting the grayscale previews
In all the screen shots you have seen so far, I have captured all these with the key held down as I dragged on the sliders. In the case of the Amount and Radius adjustments, holding down the key allows you to preview the effect these two adjustments have on the full color image by displaying a grayscale image which shows the sharpening effect as applied to the luminance information only.
One of the things that has long been known about the conventional Photoshop unsharp masking method is that a ‘normal mode’ unsharp mask filter effect sharpens all the color channels equally. It is mainly for this reason that people have in the past strived to sharpen the image luminance detail only, without actually sharpening the color information. This is what the ‘convert to Lab mode, sharpen the Lightness channel and convert back to RGB mode’ technique is doing. The