Abstract: A process for the maceral analysis of a sample of crushed coal coated with resin includes the steps of scanning the surface of the sample with a microscope and measuring the reflectance of the vitrinite. The process further includes the steps of forming a digitized image having gray levels for each field of the microscope and eliminating those fields having a high resin content. In those fields which are not eliminated, the distribution of gray levels and gradients are determined, a binary image is formed by thresholding the gray gradients to determine zones of vitrinite, the distribution of the gray levels of the obtained zones of vitrinite are then determined and the reflectance of the vitrinite is calculated.