“…However, in a number of papers published recently, including some in prestigious journals in the field of Materials Science, some inconsistencies have been detected when the subject matter is the K-M model and the so-called Tauc plot [17][18][19]. Specifically, the most serious problem consists in determining of the band gap energy directly from the plot of the Kubelka-Munk function versus incident photon energy [20][21][22][23].…”