Abstract: An apparatus and method for inspection of metallic surfaces before subsequent treatment thereof (for example, painting) are disclosed. In accordance with the invention, several light sources illuminate the inspected surface with light beams having different wave lengths, reflected radiation is detected and converted to electrical signals, the electrical signals are processed digitally, and the results of processing are displayed. Some of the light sources are mounted so as to produce light beams inclined with respect to the inspected surface. These light beams are defined by an angular divergence of not more than 5 degrees. Display of results can be presented, in terms of the ISO standard, for inspection and assessment of industrial steel surfaces (i.e., in terms of preparation grades).