2D_colorimetric_thickness We provide a colorimetric method based on optical imaging for the quantitavie determination of the thickness of exfoliated 2D materials on arbitrary substrates. Requirements MATLAB Code generate_color_bar.m calculates the aparent color in reflection of a 2D material on a arbitrary substrate as a function of its thickness. Inputs include thicknesses and refractive indices of the multilayer system, illuminant (light sources of the microscope), observer, numerical aperture of the objective. Generates your_color_bar.jpg (plot of the apparent color as a function of the thickness of the 2D material) and thickness_colorcoordinates_matrix.txt (file containing a matrix with the RGB coordinates for each thickness of the 2D material). calculate_thickness.m Inputs include RGB color coordinates extracted from the micrograph image and the corresponding file generated by generate_color_bar.m i.e., thickness_colorcoordinates_matrix.txt. Generates the estimated thickness. Related publication Full description at: Gutiérrez, Y.; Santos, G.; Giangregorio, M.; Dicorato, S.; Palumbo, F.; Saiz, J.; Moreno, F.; Losurdo, M. Quick and Reliable Colorimetric Reflectometry for Thickness Determination of Low Dimensional GaS Exfoliated Layers by Optical Microscopy. Opt. Mater. Express (2021), 11 (11), 3697.