# Configuration and the Preferences dialog

A variety of configuration options are available in the Preferences dialog. These options affect the performance, behavior, and appearance of Noise Ninja.

On Macintosh, you can access the Preferences dialog in the Noise Ninja menu. On Windows, it is located in the Edit menu. The dialog has overview buttons on each page that you can click for basic help. You can also use the "What's This" help to obtain descriptions of individual options.

## Image cache

Set the "RAM usage" slider on the Image Cache page to an amount that is appropriate for your computer. Generally speaking, the more memory you allocate to Noise Ninja, the faster and more smoothly it will run. However, Noise Ninja uses some sophisticated caching and disk swapping schemes that allow it to process large images even when memory is limited. 256 to 512 megabytes should be adequate for most users. After you have set the memory usage level, restart Noise Ninja so the change will take effect.

> Tip: A rule of thumb is to allocate 20 bytes per pixel. If you are filtering a 6 megapixel image, for instance, then try to have at least 120 megabytes allocated to Noise Ninja's image cache.

Noise Ninja creates a scratch file to hold image data that doesn't fit in memory. The scratch file is deleted automatically when Noise Ninja terminates. By default, it is located in a system temporary directory, and this is usually fine. If you want, you can change the scratch file location by clicking on the "Change" button on the Image Cache page. The scratch file can grow very large if you open many images at once or if you work with large film scans, so be sure to locate it on a volume with plenty of free space. Also, make sure to choose a directory where you have permission to create files.

## File Save behavior

On the File Save Behavior page, you can control what happens each time you save a file.

"Invoke Save As on first Save" will display the Save As dialog the first time you try to use the "Save" function for a dialog. This can help to prevent accidental overwrites.

The option to "Remember directory for Save As" causes Noise Ninja to open the Save As dialog in the same location where the last Save As operation took place. This allows you to open original files in one directory and save filtered files in another without having to navigate back and forth each time.

The "Default suffix for Save As" is automatically appended to the current file name when you invoke the Save As command. You can still edit the name in the Save dialog. Also, the suffix is not added if it is already present in the file name.

If you enable the "Show Tiff options dialog" or "Show Jpeg options dialog" options, then a dialog will allow you to configure various file attributes each time you use the Save As function. However, you might find it more convenient to configure these settings once by pushing the "Set options" buttons, and then clear the checkboxes. This will prevent the dialogs from being displayed when you use the Save As command.

## Noise profiles

On the Profiles page, there are options to control saving and automatic loading of noise profiles.

The option to "Propose a name based on annotations" will automatically generate a profile name using the Manufacturer, Model, ISO, and other annotation values if they are present in a noise profile. This naming scheme is completely optional, it will not affect the operation of Noise Ninja in any way.

The option to "Create folders automatically" should be enabled if you are using the automatic profile loader. It uses the Manufacturer and Model annotations in a profile to propose a location for a profile when you save it. This will help to ensure that profiles are stored where the auto loader can find them.

The Profiles page also contains a checkbox to "Auto-load best-match profile" This controls the automatic profile loader. Check this box if you would like Noise Ninja to select and load profiles automatically when you open an image. Click on the "Set match criteria" button to configure the auto loader.

## Multiprocessing

Multiprocessing allows noise removal and profiling to run on more than one processor to accelerate computation. It requires that you have a computer with two or more processors, or a processor that supports hyperthreading. In addition, multiprocessing requires a Professional license.

To activate multprocessing, go to the Multiprocessing page and choose the appropriate level of multiprocessing support. You can try different settings to see the effect. For a dual-processor computer, four threads seems to work the best.

## Miscellaneous options

Some additional options are located on the Other page.

The "Use muted colors for icons" option will desaturate the icons in the Noise Ninja user interface so that they are less distracting.

The "Animate selections" option activates a marching-ant effect for the filter preview rectangle and for profile selections. These can make the selections easier to see, but some people prefer a static display.

The "Zoom on load" option determines whether an image is fit within the viewing window, or zoomed to 100% magnification when the image is loaded. Since you normally want to preview noise filtering at 100% magnification, this option can save a step in the work cycle.

The "Filter preview size" option determines the dimensions of the noise filter preview rectangle. On a slower machine, a smaller rectangle might make the filter tool more responsive and easier to adjust.

Check "Set default sharpening to zero" to reset the sharpening amount on the Noise Filter page to zero whenever you open an image or load a profile.