https://doi.org/10.1351/goldbook.08631
\(f(R_{\infty}) = (1 – R_{\infty})^{2}/2R_{\infty}\), where \(R_{\infty}\) is the diffuse reflectance from a sample of infinite depth.
Note: Theoretically \(f(R_{\infty})\) equals the ratio of the linear decadic absorption coefficient to the scattering coefficient. Under the assumptions of the Kubelka Munk theory, if the scattering coefficient at a given wavenumber is a constant for a given set of samples, \(f(R_{\infty})\) is directly proportional to the product of the absorption coefficient and concentration of each component of a mixture, analogous to the behaviour of absorbance under Beer’s law.
See also: volume reflection