A developed identities for the reflectance R and the transmittance T for thermally deposited percolated gold films of thickness (D<<) - at low deposition rate have been investigated at a definite wavelength near the IR-region of spectrum (2.5 ≥λ≥1.5 μm) - taken into account the mechanism - of optical absorption caused by percolating conducting electrons and/or cluster modes as well as - of excitation of surface plasmons as a result of the granular effect of the investigated film. The calculated values of R and T are in accordance with published experimental - and calculated data.