Interference reflection microscopy (IRM) and backside absorbing layer microscopy (BALM) have emerged as powerful optical microscopy methods for the study of nanomaterials and biological samples. These techniques consist in using an inverted optical microscope in reflection mode to observe objects deposited either on glass (IRM) or on a nanometric absorbing metallic film (BALM). The thickness of the BALM absorbing layer and of optional additional transparent layers, as well as the choice of incident wavelength and top medium, act as powerful levers for maximizing the resultant contrast of a given sample. However, the use of BALM to study samples with high absorption coefficient has been limited so far in the literature. Furthermore, the complex refractive index (