A method for obtaining a reflectance property indication of a sample which includes making a reflectance measurement of the sample and correcting the reflectance measurement in order to obtain the reflectance property indication. The reflectance measurement represents an observed reflectance of the sample, the reflectance property indication represents a standardized reflectance of the sample, and correcting the reflectance measurement accounts for a difference between the standardized reflectance and the observed reflectance. An apparatus for making a reflectance measurement of a sample which includes a housing defining a viewing port, a temperature control mechanism for controlling the temperature within the interior of the housing, and an optical reflectometer contained within the interior of the housing. The reflectometer has a measurement direction and is movable within the housing so that the measurement direction can be selectively aligned with the viewing port.