The research analyses the variation of the surface chromatic properties, hue and brightness, sustained by the Portland cement mortar support, due to the application of anti-graffiti protective treatments. The test specimens were digitally analysed using a methodology based on the RGB model, which resulted in the image histogram values of each test specimen treated. The same mortar type without protection was used as the base to quantify the modification. Surface chromatic variation is determined by the type of anti-graffiti treatment used and by the base material on which it is applied. The result is that all the anti-graffiti products studied cause the variation of the supports’ hue and brightness, with the mortar made from grey Portland cement type CEM II/B-M(V-L) 32,5 N (Mb) being the one with less variation of its surface chromatic characteristics once treated. In addition, the fluorinated acrylate component (A4) causes the smalles deviation of the absolute hue and brightness values obtained from the samples analysed.