Some of the existing studies present rather broad library of
Raman or infrared spectra of natural organic substances such as
binders or varnish materials [6,7], or fresh plant substances [16],
or even biological and pharmaceutical compounds [17–19]. Other
studies present particular tools to distinguish between some
organic compounds using simple criteria, such as bands presence
and absence, or band shifts [20–22]. However, these approaches
are limited by the similarity between all these natural substances'
spectra, or by the spectra evolution due to the alteration processes
of such materials. But nearly all other published works are specific
case studies of one or two substances that were found on a piece
of art or archeological artifacts, and do not present an important
amount of media, or any specific methodological development for
indentifying them [23–30]. Moreover,these studies deal with only
one of the two presented vibrational spectroscopies.