PROCESSING YOUR DATA
 
Baseline Correction
Even after phasing is complete, some spectra still exhibit baseline artifacts. One commonly encountered type is baseline roll, in which an undulating component is seen across the entire baseline. To compare a spectrum with baseline roll to one without, move your mouse into and out of the area below:
 
Correction of such baseline artifacts may be performed by software routines which may be completely automated or partly manual. The basic approach is the same in either case. First, the baseline rolls are mathematically approximated by a polynominal. The software (or the user), selects several points (shown below in blue) along the baseline, which are then fit to a polynomial chosen by either the computer or the operator. Roll your mouse over the image below to see the resulting polynomial (in tan) displayed under the original spectrum (in green):
The resulting polynomial function is then subtracted from the original spectrum.
 

In simple situations like the one shown above, such automated correction usually works quite well. However, if the baseline artifacts are complex, or if the spectral peaks are very broad, highly automated routines may create more problems than they solve. In such cases, some user intervention may be advantageous.