The paper by P. Blake, E. W. Hill, A. H. Castro Neto, K. S. Novoselov, D. Jiang, R. Yang, T. J. Booth, and A. K. Geim explores the visibility of graphene on SiO₂ substrates using optical microscopy. They find that graphene's visibility strongly depends on the thickness of SiO₂ and the wavelength of light used. By using monochromatic illumination, graphene can be isolated for any SiO₂ thickness, with 300 nm and approximately 100 nm being the most suitable for visual detection. The authors develop a Fresnel-law-based model to quantitatively describe the experimental data, showing excellent agreement between theory and experiment. This model allows for the optimization of contrast and the detection of graphene on various substrates, including Si₃N₄ and PMMA. The study provides a quantitative framework for detecting single and multiple layers of graphene and other two-dimensional atomic crystals on different substrates.The paper by P. Blake, E. W. Hill, A. H. Castro Neto, K. S. Novoselov, D. Jiang, R. Yang, T. J. Booth, and A. K. Geim explores the visibility of graphene on SiO₂ substrates using optical microscopy. They find that graphene's visibility strongly depends on the thickness of SiO₂ and the wavelength of light used. By using monochromatic illumination, graphene can be isolated for any SiO₂ thickness, with 300 nm and approximately 100 nm being the most suitable for visual detection. The authors develop a Fresnel-law-based model to quantitatively describe the experimental data, showing excellent agreement between theory and experiment. This model allows for the optimization of contrast and the detection of graphene on various substrates, including Si₃N₄ and PMMA. The study provides a quantitative framework for detecting single and multiple layers of graphene and other two-dimensional atomic crystals on different substrates.