Graphical subtraction of two spectra

Sure, it is very easy to subtract data in Igor. But you are telling us not really much about your specific case, so it is rather difficult to say anything specific. If you have two waves loaded containing the data for the two spectra in question then you could use a simple command line operation like:
waveofsprectrum1 -= waveofspectrum2
which subtracts spectrum 2 from spectrum 1 and overwrites the data of spectrum 1 with it (with certain assumptions). There are many ways to do this. For example, another possibility would be to use the Wave Arithmetic package in the analysis menu.

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Chozo's example works for two data sets with the same number of points, and the X values for each data point. That would be the case if both data sets use the same X wave, identical X waves, or they both use the same X scaling.

You might be interested in the Wave Arithmetic package. See the demo under File->Example Experiments->Analysis->Wave Arithmetic Panel Demo.

This package handles overlapped but not identical X ranges, and differing X spacing.

John Weeks
WaveMetrics, Inc.
support@wavemetrics.com

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Thank you for your response! @chozo: The command line operation you wrote was the one I was looking for, thanks!
Best regards!

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