From the equation above and the known refractive indices, reflectivities for both interfaces can be calculated, denoted "R"01 and "R"1S respectively. The transmission at each interface is therefore and . The total transmittance into the glass is thus "T"1S"T"01. Calculating this value for various values of "n"1, it can be found that at one particular value of optimal refractive index of the layer, the transmittance of both interfaces is equal, and this corresponds to the maximal total transmittance into the glass.