Computer-Assisted Infrared Analysis of Heterogeneous Works of Art

In this paper a simple elaboration of the infrared spectra ofheterogeneous materials is outlined. The data processingmethod, based on the least-squares solution of overdeterminedsystems, allows the semiquantitative analysis ofmixtures in terms of the spectra of their components. Anapplication of the data processing logic to a two- and threecomponentsmixture is shown, but the method can beapplied to more components with no difficulty. The proposedalgorithm requires few instructions in a spreadsheetmacro and can be applied fruitfully to the Fourier transforminfrared spectra of materials of historic and artistic value,which generally do not allow chemical manipulation for theanalysis of the samples.