The optical properties of graphene, including reflectance and transmittance, are analyzed as functions of frequency, temperature, and carrier density. The study reveals that these properties are primarily determined by direct interband electron transitions. At low temperatures, the real part of the dynamic conductivity in doped graphene takes a universal constant value, while the imaginary part diverges logarithmically at the threshold of interband transitions. The paper also discusses the impact of charged impurities on carrier relaxation and provides a detailed theoretical framework for calculating the conductivity in different regimes. The optical properties of both monolayer and multilayer graphene are examined, with specific attention to the role of the underlying substrate and the influence of carrier concentration. The results show that the reflectance and transmittance exhibit distinct behaviors, with the intraband conductivity dominating at low frequencies and the interband absorption playing a crucial role at higher frequencies. The study concludes by highlighting the importance of these findings for understanding the optical properties of graphene and their potential applications.The optical properties of graphene, including reflectance and transmittance, are analyzed as functions of frequency, temperature, and carrier density. The study reveals that these properties are primarily determined by direct interband electron transitions. At low temperatures, the real part of the dynamic conductivity in doped graphene takes a universal constant value, while the imaginary part diverges logarithmically at the threshold of interband transitions. The paper also discusses the impact of charged impurities on carrier relaxation and provides a detailed theoretical framework for calculating the conductivity in different regimes. The optical properties of both monolayer and multilayer graphene are examined, with specific attention to the role of the underlying substrate and the influence of carrier concentration. The results show that the reflectance and transmittance exhibit distinct behaviors, with the intraband conductivity dominating at low frequencies and the interband absorption playing a crucial role at higher frequencies. The study concludes by highlighting the importance of these findings for understanding the optical properties of graphene and their potential applications.