Noise Reduction and Sharpening


Today’s Question: In the Detail section for Adobe Lightroom or Camera Raw what do you suggest for the different slider values for both reducing noise and sharpening the image?

Tim’s Quick Answer: As a general rule, the sharpening applied to the initial raw capture (not for final output) should be minimal, so that it is just enough to compensate for a loss of fine detail in the original capture. Noise reduction should generally be applied in moderation as well, to avoid reducing the sharpness and color accuracy of the image.

More Detail: In some respects, sharpening and noise reduction are performing opposite tasks, and so it is important to be careful not to get too aggressive with one at the detriment of the other.

For sharpening, the key settings are Amount and Radius. The Amount value controls the strength of the sharpening effect, and in Lightroom or Camera Raw I recommend keeping the value for Amount below about 75. Generally, a value somewhere between 25 and 50 will work well for most images.

For the Radius slider, you will generally want to use a value of 1.0 or lower. For images with significant fine detail you may want to use a lower value of around perhaps 0.6 to 0.9, using a slightly higher value for Amount to compensate. For images without much fine detail, you might want to use a higher value for Radius (perhaps as high as 2.0), but with a lower value for Amount to compensate for the larger size of the sharpening effect.

The Detail and Masking controls enable you to limit the sharpening to only the areas that contain detail and texture. Increasing the value for Detail will result in more enhancement of details in the photo. By contrast, increasing the value for Masking will enable you to focus the sharpening effect to only areas with texture, so that smooth areas of the photo will not be sharpened.

For noise reduction, the key settings are Luminance (for noise exhibited by variations in tonal values) and Color (for noise exhibited by variations in color values). The Luminance and Color sliders control the strength of the noise-reduction effect. Obviously you want to make sure you apply enough noise reduction to improve the appearance of the photo. It is important, however, not to use a value that is too high, as doing so can degrade image quality.

The Luminance slider is the more critical of these two, because increasing the value for Luminance to a high value will seriously degrade the texture and detail in a photo, adding what is essentially a blur effect. I try to limit the value for Luminance to around 10 or so, recognizing that this is a compromise when noise is significant in the photo.

You can be a little more aggressive with the Color slider, and I consider values up to around 60 or so to be safe in most cases. Going too high can result in some unwanted blending of colors in the photo, especially along edges where different colors meet.

For both the Luminance and Color noise reduction adjustments, I recommend using a rather low value for Detail. I try to keep this setting below about 25. When using a higher value for Detail you’ll want to make sure that you aren’t seeing individual pixels appearing that strongly contrast with surrounding areas, as this is a common side-effect of a value for Detail that is too high.

For Color noise reduction you can generally use a rather high value for Smoothness, which can help blend color variations left behind by color noise reduction, and greatly enhance the final effect. I often use a value of 80 or more for the Smoothness slider.

It is important to keep in mind that all of these settings will vary based on the content of the image you’re working on, your own preferences and priorities for the image, and other factors. Use the above information as a guide, and fine-tune as needed based on the individual image you’re working on at any given time.