1. A method to reduce background noise in an experimental spectrum, the method comprising: (a) contacting a blank sample with electromagnetic radiation, sufficient to obtain a background spectrum; (b) performing an intrinsic dimension analysis on the background spectrum, sufficient to obtain multiple correlations between variables in the background spectrum; (c) identifying and retaining the intrinsic dimensionality of the variables in the background spectrum; (d) contacting an experimental sample with electromagnetic radiation, sufficient to obtain an experimental spectrum; (e) performing a regression analysis on the experimental spectrum, based upon known characteristics of pure substances, effective to provide a simulation spectrum; (f) mathematically operating at least part of the simulation spectrum with at least part of the experimental spectrum, effective to provide a residual spectrum; (g) projecting at least part of the residual spectrum onto the intrinsic dimensionality of the background spectrum, effective to identify any etalons present in the residual spectrum; (h) mathematically operating the etalon with the experimental spectrum, effective to provide an experimental spectrum having reduced background noise.