For first-time users of Noise Ninja, this section provides a tutorial introduction to the noise reduction workflow. While it does not cover Noise Ninja in depth, it covers the most important points, and it should be enough to allow you to start using the tool productively within a few minutes.
As a general principle, you should apply noise reduction as early as is practical in your workflow — ideally, before other editing operations like tone adjustment, color balancing, sharpening, or resizing. Adjustments like these can shift pixel values and distort noise levels in unpredictable ways, and this can make it more difficult for Noise Ninja to remove the noise effectively. Sharpening and resizing, in particular, should be deferred until after noise reduction when possible. (Modest amounts of in-camera sharpening are usually okay, however.)
To load an image, click on the File Open button in the window toolbar:
Currently, Noise Ninja can read JPEG and uncompressed TIFF images.
A noise profile characterizes how much noise is present for different colors and brightness levels in an image. For instance, a noise profile can represent the fact that there is more noise in shadow areas than in highlights, or more noise in reds than in yellows. Noise profiles are the key to getting good results with Noise Ninja, because noise levels are different for every camera and scanner, and for different values of ISO sensitivity and other settings.
First, activate the Noise Profiler by clicking on the Noise Profile selector button:
Next, do one of the following:
For the moment, you can just click the "Profile Image" button. When you have time, you are encouraged to read about creating noise profiles and using the automatic profile loader.
After you have created or loaded a noise profile, activate the Noise Filter tool. This tool uses the noise profile to suppress noise from the image:
If you don't see a green preview rectangle, click anywhere in the image to activate it and position it. You can right click to turn it off, or you can toggle the Preview button:
Next, adjust the sliders until you like the results shown in the preview area. Each time you adjust a slider, the preview will be updated to show the effect of the adjustment. You can toggle the preview to see the unfiltered image.
There are three groups of sliders on the Noise Filter page. The Luminance group affects filtering of noise in the brightness component of an image. This is usually the part of the image that contains the most real information. The Colors group controls filtering of color noise, which is often the most displeasing noise. The Sharpness group enhances edge sharpness using an unsharp mask.
Strength controls how aggressively the filter is applied. This is the control that you'll normally want to adjust if you don't like what you see in the preview rectangle. If you move it far to the right, the image may look too smooth. If you move it to the left, it will look more grainy. Often the most natural-looking results are achieved when you leave a modest amount of grain. The human eye tolerates a certain amount of noise when it is accompanied by detail, and the luminance channel contains most of the detail in an image.
Smoothness increases or decreases the noise levels estimated by the Noise Profile. Usually the default setting is adequate, but if you see isolated specks in smooth areas, try increasing the smoothness setting to see if they go away. (Here's a tip for adjusting the Smoothness slider: Move the preview window to a smooth background areas, and move the Strength slider all the way to the right so the preview is a smooth as possible. Then set the Smoothness slider to the minimum level such that the preview is still smooth (if it is too low, you will usually see isolated specks). Finally, lower the Strength slider until you like the results.)
Contrast and saturation apply a scaling factor to edges, similar to an unsharp mask, but at several resolutions simultaneously. You probably won't need to adjust these in most situations.
Sharpness amount and sharpness radius apply a conventional unsharp mask to the filtered image. Some people prefer to set the amount to zero and do sharpening later in the workflow. However, even in that case, it can be useful to preview the sharpening effect to see how it interacts with the noise reduction. The Suppress halos option eliminates unnatural highlight artifacts that can occur when high sharpening levels are used.
Here is a simple strategy for adjusting the Luminance sliders that usually yields good results:
1. Set the Luminance Strength slider all the way to the right
2. Set the Luminance Smoothness slider to the lowest level that results in a smooth area without obvious speckling.
3. Reduce the Luminance Strength slider until you like the balance between noise reduction and detail preservation.
When you are satisfied with the slider settings, press the Remove Noise button to apply filter to the entire image:
After filtering, you can use the Before button to toggle between the original image with the filtered version:
Press and hold the button to view the unfiltered image.
The Noise Brush tool allows selective undo or fading of noise reduction. To use it, activate it by clicking on the Noise Brush tool selector button:
Next, use the mouse to paint on areas where you want to touch-up the results of filtering. This is typically useful for hair or fine texture, which is often difficult to distinguish from noise.There are a number of controls in the tool panel for changing the size and operation of the brush.
You can apply the Noise Brush to the luminance channel, color channels, or all channels. Usually, you'll obtain the best results by working in the luminance channel. This will allow you to touch-up detail without reintroducing color speckles.
You can flip the brush mode from undo to redo, or vice-versa, by right-clicking, alt-clicking, or control-clicking. You can also undo and redo individual brush strokes or all brush strokes by clicking on the appropriate buttons:
When you are finished processing an image, save it to your hard disk with the Save As command:
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Note that your images will be watermarked with a gray grid when you save them, unless you install a valid license key. Click here for more information about license keys.
If you want to go back and try filtering the image with different settings, invoke the Undo command in the Edit menu (or press Ctrl-Z), and then go back to Step 3.
Once you've gotten comfortable with the basic operation of Noise Ninja, here are some other features and capabilities that you should explore:
