All Photos © 2004, Peter K. Burian, All Rights Reserved

Although most digital cameras produce clean images at low ISO settings, digital noise often degrades images made at higher ISO levels. Resembling colored specks that are visible especially in shadow areas, noise can be prominent in ISO 800 and higher images made with a digital SLR. It's even more problematic with many of the high megapixel cameras that use smaller sensors. Because their light-gathering photosites are miniscule, the sensors are less sensitive to light; hence, even ISO 400 images can exhibit objectionable noise.

The PictureCode website offers numerous pre-defined profiles--for various cameras and scanners--that can be downloaded. Use one of these and Noise Ninja 2.0 should produce more accurate results than would be possible with automatic profiling.

That may not be relevant if you typically use ISO 50-200, but the higher ISO options are useful whenever fast shutter speeds are required in low light. Whether you need to shoot without a tripod, or want to "freeze" action subjects, it's great to be able to use ISO 400, 800, or even 1600. Run a test with your own camera, making some high ISO images; inspect them at 100 percent magnification on a monitor. If random colored specks are visible--and especially if they degrade image quality--you may be a candidate for noise reduction software, such as Noise Ninja 2.0.

The original Noise Ninja was one of the top-rated programs of this type but it was a bit complicated to use, somewhat slow, and available only for Windows operating systems. The new Version 2.0 addresses all three issues and also boasts more sophisticated "automatic profiling," explained later. After using Noise Ninja 2.0 for a month, I can highly recommend this new program. If some of your own images are "noisy," download the free trial version from the www.picturecode.com website.

Do note that the trial version will watermark your images, as it's intended only for experimentation.

A
B	C
D
This ISO 400 image (Photo A) was made with an 8-megapixel camera that generates noisy images at high ISO settings, a problem that should be obvious in the small segment of the full image (Photo B). Using the "Quick Auto Profile" approach in Noise Ninja 2.0 produced an excessively smooth "plastic" effect (Photo C) with this difficult scene. The final image (Photo D), processed using a custom profile, exhibits an ideal compromise: slightly more visible noise but superior sharpness, contrast, and texture. d

Basic Operation
After completing the download and installation, launch Noise Ninja 2.0 and open a JPEG or an uncompressed TIFF file that has not been extensively processed in Photoshop or other software. Select the Noise Profiler icon, resembling a bar graph. Click on the "Quick Auto Profile" icon to allow Noise Ninja to analyze the image to determine the amount of noise present in different colors and brightness levels. This detailed "profiling" is important, because the noise characteristics are different for every camera and for each ISO level. The process is useful for scanned images, too, because film scanners can introduce noise especially in dark areas and in the blue channel.

After that's finished, access the "Noise Filter" screen with the pertinent icon and click on the "Remove Noise" button. In about 10 seconds, the software will process the image, filtering (removing) noise at a predetermined level. The image will now appear noticeably smoother, exhibiting substantially less digital noise. The colored specks that remain will also be less saturated, and hence, less noticeable.

The Noise Brush tool offers the user a great deal of post-processing control for selectively modifying the noise reduction filtration.

Evaluation: The automatic noise analysis and filtering process is certainly simple and quick; it's also quite effective with some images. The system is most successful when it can sample large areas without detail, preferably mid tones. With images that include vast expanses of shadow areas, or a great deal of detail, the filtration can be excessive, producing an overly smooth, "plastic," effect. Although Noise Ninja 2.0 also offers a feature that allows the user to select the image areas to be sampled, that process is a bit tedious and relies on some guesswork.

Advanced Operation
Instead of using profiling to analyze each image, take advantage of the noise profiles available at: www.picturecode.com. Download the files for your camera (or film scanner). Use the correct profile--designed for images produced by a specific camera at a specific ISO level--and you'll get more satisfactory noise reduction with a broader range of image types. If you forget the ISO you set, open the Exif file data and the specs will be shown.

The Noise Ninja 2.0 software screen provides a large, crisp preview image and many well-marked controls for great convenience of use.