#41 Sharpening and Reducing Noise
The Sharpening and Noise Reduction controls are located on the Detail tab (Figure 41).
Figure 41 The Detail tab.
To achieve the best results with these controls, be sure to change your zoom level to 100%. Choose the zoom level from the menu on the lower left of the Camera Raw window.
The type and intensity of sharpening that you apply is contingent upon the image. Because of the many variations in photographs, sharpening is more of an art than a formula. To sharpen effectively, you need to learn about the basic principles, and then apply those to a particular image. In Camera Raw, the Sharpening sliders affect only the luminosity information in the image—that is, the light and dark values of each pixel. Color information is not changed.
Typically, it is best to begin your adjustments using the Amount and Radius sliders on the Detail tab, which control how much sharpening is applied to the entire image and how it is applied. Then move on to the Detail and Masking sliders to dial back the sharpening in certain areas:
- Amount slider. Adjusts edge definition. A value of zero equals zero sharpening. Increase the Amount value to sharpen the whole image. Typically, it is best to set a lower value for this control, because high values tend to create “halos,” or visible artifacts, around sharpened areas.
- Radius slider. Adjusts the size of the details to which the sharpening is applied. The correct Radius setting will depend on the image. If you have an image with fine details, try a lower radius setting; if your image is dominated by large objects, try a higher radius.
- Detail slider. Tones down the halos added by the Amount slider while keeping edges sharp. A setting of 0 gets rid of halos almost entirely, and a setting of 100 preserves them. For blurry images, try a lower setting. To emphasize texture, try a higher setting.
- Masking slider. Applies a mask to the sharpening that protects relatively smooth areas that don’t need much sharpening and concentrates the sharpening along the edges of items. (I’ll talk about masks in Chapter 5, “Working with Layers,” but for the moment just remember that in Photoshop a mask is a technique for protecting part of an image from editing, like masking tape). With a Masking slider setting of zero, everything in the image receives an equal amount of sharpening. With a setting of 100, sharpening is mostly limited to the strongest edges.
The Noise Reduction sliders can be used to improve images that have noise (visible artifacts that degrade the image). Noise often occurs as a result of shooting with a high ISO, improper exposure, or a low-quality digital capture. These sliders are not a cure-all for noise, but for many of us they are a regular step in our photographic workflow.
Drag the Luminance slider to the right to reduce grayscale noise. This will smooth out the irregular shape and size of noise. Drag the Color slider to the right to reduce color noise. Typically, the default Color Noise amount of 25 will be more than sufficient. In fact, most of the time it’s best to choose an amount below 25. When reducing noise, be careful not to increase the settings so high as to oversoften the image. If the image does become soft, be sure to increase the overall sharpening amounts. In fact, that’s why the Noise Reduction and Sharpening controls are located in the same panel!