This method is designed to enhance the accuracy of spectrophotometric data needed in (a) the measurement and control of the color of paper, and in (b) research on the optical properties of paper. It is intended to cover instrumental procedures for both spectral reflectance factor and trans-mittance of paper, paperboard, and pulp.
Data obtained in accordance with this method will be most accurate for materials that meet the following requirements:
The face of the material presented to a measuring port of the instrument is flat and free of indentations and touches the whole perimeter of the port when under moderate force.
The nature of the material and its backing are such that the specimen does not bulge appreciably into the space beyond the plane of the port.
A single sheet of the material that is sufficiently opaque to minimize the so-called edge effect.
