You can choose among many methods for automatic phase correction. Some algorithms have a wider scope,
others are more specialized. There are methods for 1-D spectroscopy
and others for 2-D spectroscopy. The most important method in each category is listed first.
Sometimes it is useful to apply the same algorithm twice, because
the optimal correction is not found at the first attempt. That's why it's a good idea to use a shortcut
instead of the menu command.
To obtain accurate results it is normally necessary to refine the correction manually.
In 3-D spectroscopy, only the manual correction is possible.
The baseline is flat or V-shaped.
The side regions don't contain peaks.
Most of the peaks are positive.
If you have created marks into the window, delete them (for example, with ⌘-alt-double click on the Mac; Alt-Alt Gr-double click on Windows ); then:
either Choose Process > Automatic Phase.
or Click the corresponding palette icon (blue dispersion signal with a gear).
or Press ⌘-alt-K (on the Mac) or Ctrl-Alt-K (on Windows).
All the peaks are positive.
either Do nothing, because iNMR automatically applies this method to new 1-D documents.
or Create an horizontal mark (with alt-click), then Choose Process > Automatic Phase or any of the equivalent shortcuts.
You have both positive and negative peaks.
There are two or more sharp singlets.
Mark two or, preferably, more singlets with ⌘-click (on the Mac) or Alt Gr-click (on Windows).
Choose Process > Automatic Phase or any of the equivalent shortcuts.
in the first instance.
Verify that no region is selected.
Choose Process > Automatic Phase or any of the equivalent shortcuts.
the global method does not work.
The spectrum must be hyper-complex.
Select a region (the algorithm will try to make positive the peaks internal to it).
Optionally create an horizontal and/or a vertical mark. The phase will not be corrected at the frequency of the marks, if they don't intersect the selected region.
Choose Process > Automatic Phase or any of the equivalent shortcuts.
Those automatic algorithms that can handle both positive and negative peaks, may incorrectly produce a spectrum rotated by 180°. To counter-rotate it by another 180° you can use the shortcut ⌘-control-K (on the Mac) or Ctrl-⇧-K (on Windows).