Paint Analysis Using Visible Reflectance Spectroscopy: An Undergraduate Forensics Lab

Low-Cost Multispectral Imager

“…The MSI described here is a low-cost device, which is sufficiently simple in its construction and use, to become a useful tool in the teaching of undergraduate chemistry courses concerned with the concepts of spectroscopy, − chemometrics, − and colorimetry. , In addition, its analytical power is sufficient to tackle complex sample analysis tasks, which has been demonstrated through the analysis of chill injury in peach fruit. This makes the device suitable for independent student inquiry activities such as undergraduate projects.…”

“…It is suitable for application to a wide range of imaging and sample analysis tasks. Many undergraduate and postgraduate courses include the topics of spectroscopy, − chemometrics, − and colorimetry. , The multispectral imager (MSI) described here could be a useful teaching aid for many of these courses. At an introductory level, it provides an intuitive and hands-on way for students to understand the basics of spectroscopy, while at a more advanced level it provides opportunities for students to develop skills in the essential chemometric multivariate analysis techniques of principal component analysis and k-means clustering.…”

Identification of Synthetic Organic Pigments in Contemporary Artists’ Paints by FT-IR and FT-Raman: An Advanced Analytical Experiment

“…Other laboratory experiments that deal with chemistry for the characterization of coloring substances in art have been proposed. These include the use of visible reflectance spectroscopy for the identification of pigments , and the application of Raman and SERS spectroscopy for the investigation of red natural colorants . Moreover, the synthesis of several inorganic pigments combined with different historical binders to create a paint has been proposed to give students the opportunity to learn what paints are made of and how, acquiring in the meantime simple chemical concepts such as stoichiometry, precipitation, and solubility. − …”

Characterizing Color with Reflectance

“…As evidence, a 2012 survey of UV−vis spectrophotometers in the undergraduate chemistry curriculum 1 cited just a single application of reflectance spectroscopy. 2 Second, absorbance measurements in the UV−vis region are restricted to transparent samples and cannot be made on opaque solids, the end result of many laboratory syntheses, unless they are first dissolved in a solvent. Although serviceable, absorbance (and transmittance) spectra of a solution are one step removed from the observed color of the solid and, given the availability of reflectance spectrophotometers, an unnecessary compromise.…”

“…In an experiment cited in the 2012 survey, 1 students in a forensic-science course match a "paint smear" to one of a set of white house paints tinged with blue by comparing their CIE L*a*b* color coordinates. 2 An article inadvertently overlooked by the survey describes a trio of experiments, suitable for a nonmajor artconservation course and analytical and analytical−instrumental courses, involving analysis of reflectance curves and L*a*b* coordinates of samples collected from paintings. 5 A recent contribution to this Journal uses transmittance spectra of indicator solutions and wines as the basis for computing color coordinates.…”