Typical Procedure
1. Open the set of files you want to process. You can select the menu option to open the files or use the toolbar icon. If the images are light images (as opposed to dark frames) then they must have already been dark subtracted, optionally flat-fielded, and registered. Sigma works best when you are combining 10 or more images but only requires 3 images.
2. Once the files are loaded you can use the keyboard (see table below), the menu, or toolbar icons to view the "noise" in your images by viewing the minimum, maximum, median
3. Process the files by using the menu or the toolbar icon. See the recommended settings section below for the settings for each type of image.
4. Using the toolbar or menu you can quickly toggle between the images. You can also use the hot keys defined below:
| Image | Press Key |
| Minimum | Keypad-/ |
| Maximum | Keypad-* |
| Median | 'M' or 'm' |
| Average | 'A' or 'a' |
| Average of Medians | 'O' or 'o' |
| Processed | 'P' or 'p' |
| Individual | 'I' or 'i' |
| Next Image | '.' or '>' or 'I' or 'i' |
| Previous Image | ',' or '<' |
5. To make changes to the processed image you need to go back into the process image dialog, make a change, then press OK.
6. You can zoom up to 8x the size (status bar on the bottom shows the current zoom magnification). Zoom hot-keys are:
| Zoom in | Keypad-Plus |
| Zoom out | Keypad-Minus |