Abstract: To form a map of the characteristics of a microscopic specimen, the specimen is supported on a slide and a point on the specimen is subjected to either polychromatic radiation or a series of monochromatic radiations of varying wavelengths employing a condensing optical system. The resulting radiation from the point is gathered by an optical system and detected either by a single wide band detector in the case of the series of monochromatic radiations or a group of frequency selective detectors in the case of polychromatic radiation, to develop a set of signals having values which are functions of properties of the point as analyzed at the different wavelengths. The specimen is either repeatedly translated relative to the radiation source or imaged once or several times so that a signel set is derived from each elemental point on the area of the object to be analyzed in each spectral band of interest.