Abstract: A wavelength correction function provides corrected reflectance values from actual reflectance values taken in a reflectance-base instrument. The correction is provided as a function of measured reflectance values and a predefined set of high resolution reflectance values established for the reflectance-based instrument implementing the wavelength correction function.

Abstract: A reflectance spectroscope, which is provided with one or more optical paths which prevent substantially all singly reflected light rays from reaching the intended destination(s), is provided with a source of illumination for generating light rays, a support member adapted to support a reagent pad, the support member having a position in which the reagent pad is illuminated by the light rays generated by the illumination source, a reflectance detector positioned to receive light rays from the reagent pad, and means for defining an optical path in which substantially all singly-reflected light rays are prevented from reaching the intended destination. The optical path may be between the illumination source and the reagent pad, or between the reagent pad and the area in which the detector is provided.

Abstract: A reflectance photometer for quantitatively measuring diffuse light includes a light source located above a sample. The reflectance photometer also includes a first detector mounted at a preselected scattering angle relative to an axis extending perpendicularly from the sample through the light source. A first linear polarizer is mounted between the sample and the light source. The direction of polarization of the first linear polarizer is vertical to a scattering plane defined by the direction of incoming light from the light source and the direction of reflected light detected by the first detector. A second linear polarizer is mounted between the sample and the first detector. The direction of the second polarizer is parallel to the scattering plane. The reflectance photometer can include a second detector mounted at a second, scattering angle. A third linear polarizer is mounted between the sample and the second detector.