Reducing Noise in Photoshop -- Part IV

Article and Photography by Ron Bigelow

Photoshop CS3 (Beta) Used in this Tutorial

Camera Raw

Figure 1: Noisy Image

The noise reduction techniques presented in the previous articles can be used with any file format that Photoshop will support (e.g., JPEG, TIFF, and PSD). In addition, those who use raw have another noise reduction choice. They can use the noise reduction option in the raw converter (i.e., Camera Raw).

Figure 1 shows an image with a noise problem. The noise becomes obvious when a 100% crop of the image is viewed (see Figure 2). 

Figure 2: Crop of Noisy Image
The first step is to open the file in Camera Raw. Then, the Detail tab is clicked to reveal the noise reduction options (see Figure 3).
Figure 3: Detail Tab in Camera Raw

The noise reduction is very simple. There are only two controls:

It is necessary to find a balance where the noise is reduced, but the detail is maintained as much as possible (this image required a lot of noise reduction). Some experimentation yielded the settings shown in Figure 3.

I recommend turning the sharpening off so that the sharpening can be handled separately.

Figure 4 shows a 100% crop of the image without the noise reduction. Figure 5 shows the crop with the noise reduction.

Figure 4: Image without Noise Reduction
Figure 5: Image with Noise Reduction

An examination of Figures 4 and 5 shows that the noise reduction has improved the image. However, there is still a significant amount of noise left.

If so desired, one can use the edge technique to add more detail back into the image. In that case, two conversions would be necessary (one image with noise reduction and one without). The image without any noise reduction should be used as the Background layer, and the image with the noise reduction would be place above it.

Noise Reduction Software

Figure 6: Noisy Image

For those photographers who are willing to spend a little cash, there are noise reduction programs that can be purchased. Some of these programs are stand-alone programs, and some are Photoshop plug-ins. While these programs are generally easy to use, at least some of them offer a noise reduction capability that is hard for most photographers to match on their own. The program that I use is called Noise Ninja.

To demonstrate the noise reduction capabilities of Noise Ninja, I deliberately shot an image with just about the worst noise characteristics that my equipment is capable of producing (older camera with the highest ISO possible). The result is Figure 6. Looking at a crop of this image (see Figure 7), one sees a very bad noise problem. Generally, I would curse myself for producing an image like this. Then, I would destroy it before anyone else got a chance to see it. However, in this case, I will use Noise Ninja to save the day.

Figure 7: Crop of Noisy Image
Once the image is open in Noise Ninja, the Noise Profiler is opened by clicking on the Noise Profiler icon in the upper left corner of the software (see Figure 8).
Figure 8: Noise Profiler
Figure 9: Noise Profile Dialogue Box
Clicking on the Noise Profile icon opens the Noise Profile dialogue box (see Figure 9). The profile for the camera and ISO is selected.

Next, the Noise Filter is opened by clicking on the Noise Filter icon (see Figure 10). There are numerous controls. However, two of them are of primary interest:

As with the controls on the other noise reduction techniques, it is necessary to play with these two settings to find the best combination that reduces the noise but leaves as much detail as possible. Clicking on the Enable/Disable Preview Region icon creates a box on the image that shows what the image will look like after the noise reduction has been performed. Lastly, the Remove Noise icon is clicked to start the noise reduction task.


Figure 10: Noise Filter
Figures 11 again shows the crop of the image before the noise removal. Figures 12 shows the same crop after the noise removal.
Figure 11: Crop before Noise Removal
Figure 12: Crop after Noise Removal

Frankly, the reduction of the noise, while still maintaining detail, is rather impressive.

One thing to keep in mind is that Noise Ninja does not supply noise profiles for all cameras. If noise profiles are not provided for your camera, you can create your own using a target supplied by Noise Ninja.

The edge technique can be used with Noise Ninja, but it may not be needed.

Some Parting Thoughts

The best method of dealing with noise is to avoid it in the first place. For this, a few things should be kept in mind.



Noise -- Part III