To remove noise from a photograph, use Edit | Adjust | Remove Noise… [Ctrl+Shift+N]. Zoner Photo Studio's noise removal function can be used to remove both the noise typical for long exposure times (sometimes called "hot pixels" noise; called "salt and pepper" in the program) and additive noise. Both of these removal types can also be applied at the same time.
Remove "salt and pepper" noise – for this type of noise reduction there is just one control; use it to set the Noise type in the picture.
Remove additive noise – with default settings, when you are removing additive noise, you can use the Brightness and Colors sliders to set the noise reduction level independently for the picture's brightness and color elements.
Use Advanced to display the more advanced noise-reduction controls, intended for experienced users.
For better, though slower, noise reduction, or vice-versa, use the Quality setting.
Besides making global changes using the Brightness and Colors sliders, you can also selectively adjust the amount of noise reduction for individual colors or image brightness levels. For this, use the controls under Local correction, by color and Local correction, by brightness. The core of each of these controls is a color or brightness gradient, beneath a curve with several nodes. Drag the nodes to reshape the curve and thus increase/decrease noise reduction for individual colors/brightness levels. Click anywhere on the curve between existing nodes to add a new node. To delete a node, press [Del]. Use the eyedropper to select a color or brightness level directly from the picture.
Very strong noise in a picture often creates distracting color stains that persist even after noise reduction. Use Color stain removal to eliminate this problem. Choose the intensity of color stain removal carefully. Too much intensity leads to excessive loss of detail in the image.
To reduce noise smartly, so that noise is removed as much as possible, but only a few details are lost, the program must determine the picture's noise level correctly. Therefore, a rather detailed noise analysis is performed before noise reduction starts. However, in some cases this analysis can still guess the noise intensity level incorrectly, causing either incomplete or overly-aggressive noise reduction. In such cases, under Image noise intensity , change the detection method to Set manually and adjust the detected noise intensity. It can be adjusted independently for colors and brightness. We recommend setting both noise reduction sliders to 100% and adjusting the noise intensity while watching the preview, until the intensity is at a level where noise reduction is strong, but loss of image detail is still acceptably low. Then put the noise reduction level sliders back to the values you want.
Just after you call up the noise reduction filter, it analyzes the noise in the picture and then runs noise reduction. This process can take a long time on large images. However, changing most settings does not demand running the process again, and so is significantly faster.