By profiling your camera or scanner, you can improve the consistency of noise reduction, and you can improve the productivity of your workflow. The basic idea is to characterize the noise for your camera under a range of typical operating conditions, and reuse those profiles when you are removing noise from images.
It is easy to profile a camera, and it only takes a few minutes. The steps are explained below.
A profiling chart is included with the Noise Ninja distribution files. It is name calibration_chart.jpg, and it is located in the root of the installation directory. You can view it by selecting "Open profiling chart" from the File menu in Noise Ninja. The chart looks like this:
Display the chart on your monitor, or print it out on any photo-quality inkjet printer. Don't worry about color accuracy. The Noise Ninja profiler only needs to see a range of colors and tones that reasonably cover the gamut; the precise color values are not important.
Note: You can order a high-quality printed chart from www.picturecode.com. See the Purchase page on the site.
Set your camera as you normally do. For each ISO setting, take an out-of-focus photograph of the profiling chart. The defocusing should be enough that any dot patterns from the monitor or texture in the chart paper are eliminated. Otherwise, they could be mistaken for noise by the profiler.
Load each image into Noise Ninja and activate the Noise Profiler tool. Click the Profile Chart button to create a profile from the image. If you prefer, you can also create a profile using manual selection. Or, you can use the manual profiling tool to make changes to the automatically-generated selections.
NOTE: The automatic profiler discards redundant selections (that is, selections that are similar in color or tone to other selections). So, don't be surprised if it doesn't select every square in the chart, because some squares in the chart are similar in color and tone. The most important thing is for the profile to cover a range of representative colors and tones in the gamut.
Go to the Annotations page to assign annotations to the profile. This is particularly important if you intend to use the profiles with the automatic profile loader. It is best to use the Auto Fill button in the annotation editor to fill in fields directly from the EXIF data in the image (if present). For more information about editing annotations, click here. To learn how annotations are used by the automatic profile loader, click here.
The procedure for profiling a scanner is identical to the one outlined above, except that you need to process and scan the film normally after photographing the chart.
Realize that noise is a function of the combination of the scanner and film, because of the way the film grain interacts with the scanning process. So, as a general rule, you will need to profile each type of film that you use with a particular scanner.
If you have a Q60 (IT8) slide target for the particular film that you use, then you can use that instead of taking photos of the Noise Ninja profiling chart. Just scan the target like you normally do, and then create a profile from the scanned image.
If you use a Q60 target, you might need to build the profile manually instead of with the Full Auto Profile feature. The Q60/IT8 targets have a number of similar patches located next to one another. This might confuse the automatic profiler, which tends to perform better when there are high-contrast edges to separate patches. If you build the profile manually, you don't need to select every patch in the target. Just select enough to cover a representative sample of the color and tone gamut.