A Review of Microcolorimetry for Textile, Food, Dental and Optoelectronic Industries

A microscope spectrophotometer may be used for colorimetry with transmitted, reflected or emitted light. Optical fibers may be used to link the microscope to remote samples, which may be commercial color standards like Pantone or paint manufacturers’ color chips, or small museum specimens. The weighted-ordinate method of colorimetry gives useful results for a wide variety of samples, although light scattering in small samples like textile fibers has some important effects that may be missed in macroscopic colorimetry. The weighted-ordinate method is applicable to metallic and pastel interference colors, with printed simulations and real interference colors giving similar results. Thus, spectrophotometry is still required to identify fake security holograms. ？Some classic work was confirmed, showing how immersion under water may be used to identify a source of iridescence. Multilayer interference in molluscan shell nacre had multiple spectral peaks easily detectable under water, whereas diffractive interference on a peacock feather had a single spectral peak lost under water.？ Iridescence in single muscle fibers from roast meat resembled multilayer interference in having multiple spectral peaks that were easily visible under water, and the importance of optical anisotropy in food colorimetry was considered. Boolean analysis of fiber-optic spectra may be used instead of the weighted-ordinate method for spectra obtained robotically in a contextual learning mode. From investigating museum samples to quality control using optoelectronic components, microcolorimetry may have a promising future.