Spectral data reduction is a crucial step, as so important as the acquisition process. Rigor shall be as well applied at this stage to not degrade the quality of the data acquired. It is the last step before the computation of the astrophysical quantities. It is thus necessary to understand what is involved in each processing steps and the underlying limitations. Thus limitations or limit conditions are usually embedded and then hidden in a specific software command that everyone use without completely mastering what is really at stake. In this chapter we will introduced the different type of processing and spectral analysis which can dispose an amateur in several software packages. The first processing will treat about basic images correction which are linked to the CCD acquisition and the processes pipeline. We will then describe the different strategy to calibrate the spectral profile in wavelength and the few corrections driven by the earth environment to increase the accuracy of the future measurements. We will end with the description of few tools on quantitative spectral analysis and their limitations. The practice of spectral acquisition and processing is just at its beginning in amateur world. We hope that this section will demystify the essential step of spectral processing and will motivate the amateur to go beyond the contemplative watching of sky wonders.