Interrelation of reflectance, R0; reflectivity, R8; TAPPI opacity, C0.89; scattering, s; and absorption, k

The following interrelationships will be found particularly useful in predicting the effect upon opacity when a change occurs in either the basis weight or the reflectivity of a sheet of paper. These interrelationships can also be used to evaluate relative contributions of different pulps, fillers and pigments to optical properties. Extensions of these procedures that are cited in the references can be used to evaluate multilayer structures such as coated paper or coated board.