The Manual tab sheet contains the parameters that are used for noise reduction.
Easy Mode only features three listbar controls with five values for adjusting the denoising. Additionally there is a listbar for sharpening. Even if these options appear a bit limited they offer enough capacity to remove the most common types of image noise and compensate for the denoising with sharpening. For more precise settings and more options please switch to Advanced mode.
The Intensity values of the Luminance Denoise group determine the intensity of the luminance noise reduction. 0% does not remove any luminance noise whereas 100% applies full denoising. You often get the best result by using a value of 50%. If you like it softer, try 75%. If you like it more grainy, try 25%.
The Reduction settings of the Luminance Denoise group control the denoising parameters and thus the effectivity of the luminance denoising. The "Low" option is meant for fine and less strong noise whereas "High" effectively removes more coarse and pronounced noise. This listbar sets the values of the Threshold, Radius and Softeness sliders of the Luminance Denoise group in Advanced mode.
The Reduction listbar of the Color Denoise group influences the denoising parameters and thus the effectivity of the color denoising. The "Low" option is meant for fine and less strong color noise whereas "High" removes more coarse and strong color noise. This listbar sets the values of the Intensity, Threshold, and Radius sliders of the Color Denoise group in Advanced mode.
The Strength setting of the Sharpness group defines the parameters of the sharpness effect. A "Low" value produces weak and fine sharpening whereas "High" applies coarser and stronger sharpening.
The Recover Saturation check box tries to recover the satuation that was lost during color denosing. Activating it is recommended if you use a High or Max value for the Color Denoise listbar. If the saturation of the image was not reduced, this check box has no effect.
Advanced mode offers more precise controls for adjusting the denoising effect. The Sharpness controls are located on the Enhance tab sheet in Advanced mode.
The Arrow Menu
In Advanced Mode there is
an arrow button in the top left corner, which you can click to display a menu
with various luminance and color denoising items. These options correspond to
the values of the Reduction list bars in Easy Mode. There is also a Reset menu
item, which resets the controls on this tab sheets to their default values.
The Listbars Check Box
Whereas you have listbar controls in Easy Mode, they are optional in Advanced mode and can be displayed with the Listbars check box. The activated Listbar check box replaces the sliders with listbar controls. To get the sliders back deactivate it again. Whereas sliders contain up to several hundreds of values, listbars only offer five to nine values as clickable items. Listbars allow an easier and faster selection of useful values.
Listbars and their corresponding sliders are automatically synchronized. But if you select a slider value that is not available in the listbar, none of the listbar items is selected. That does not mean that no value is used. The slider values always have precedence over the listbar values.
If you deactivate the Luminance Denoising check box, no luminance denoising is applied. It is equal to setting the Intensity slider to zero. Quickly activating and deactivating the Luminance Denoising check box lets you compare the image with and without luminance denoising applied.
An activated L button displays only the luminance channel of the image, which can be helpful for adjusting the luminance denoising settings without being distracted by the color noise or denoising. Click it again to display all channels of the image.
The Intensity slider or listbar controls to what extent the denoised image is used blended with the original image. At a value of 100 the fully denoised image is used. At a value of 50 the original image is equally blended with the denoised version of the image. An intensity value in the middle of the range is usually best as you avoid that the image gets too grainy or too soft. But it usually depends on the users taste if he likes a softer or more grainy look.
The Threshold control defines the threshold between noise and image details. If you set it too low, too much noise if left in the image and sometimes artifacts appear. If you set it too high, too many image details are removed and the image may get too soft. The stronger the noise in the image, the higher you need to set the Threshold value. Choosing a sufficient Threshold value is important for an effective noise reduction.
The Radius slider or listbar defines the size of the noise particles that are removed. If you set it too low, the denoising is less effective. If you set it to high, image details may be removed. The Radius value also has the biggest influence on the rendering speed of NoiseControl. Higher values result in a slower rendering.
The Softness control influences the softness of the luminance denoising, but also impacts the quality of the denoising effect. A value of zero uses a faster version of the luminance denoising algorithm, which is usually less effective. So we do not recommend using a value of zero. Values of 1 to 3 are sufficient for most cases. Higher values sometimes produce a too soft result. A good rule of the thumb is to use a Softness value that is half as high as the Radius value. Less emphasized noise may nevertheless benefit from a Softness value of 1 even if the Radius is set to 5 or 6.
If you deactivate the Color Denoising check box, no color denoising is applied. It is equal to setting the Intensity slider to zero. Quickly activating and deactivating the Color Denoising check box lets you compare the image with and without color denoising applied.
An activated C button displays the color channels of the image without the luminance information, which is helpful for adjusting the color denoising settings without being distracted by the luminance noise. Click it again to display all channels of the image.
The Intensity slider or listbar controls to what extent the color denoised image is blended with the original image. At a value of 100 the fully color denoised image is used. At a value of 50 the color denoised version of the image is equally blended with the original color channels of the image. In most cases a value of 100 should be used. Only if color denoising affects the colors of the image too much, you can try to reduce the Intensity value.
The Threshold control defines the threshold between color noise and valid color information. If you set it too low, too much color noise is left in the image. If you set it too high, too many color details are removed and the image may get desaturated. The stronger the color noise in the image, the higher you need to set the Threshold value. A value of 10 works fine for most images. For severe color noise you should try values of 15 and 20.
If you activate the Threshold check box, two Threshold sliders will appear. They let you independently define the threshold of each of the two color channels. The Cb channel consists of blue to yellow colors and the Cr channel contains red to cyan colors. Usually using the same threshold value for both channels (with deactivated Threshold check box) works fine. In rare cases there is more noise in one of the two color channels. Then using two threshold sliders lets you preserve more color details.
The Radius slider or listbar defines the size of the color noise particles that are removed. If you set it too low, some of the color noise particles may not be removed. Setting it too high usually has no adverse effects if you selected a fitting Threshold value. A value of 8 is effective for most color noise problems.