This paper proposes the implementation of digital image analysis for the easy, fast and simple description of membrane surface changes as a result of fouling or any process with capacity to produce, directly or indirectly, color changes on the surface. For that, a color amount descriptor is used to generate a quantitative measurement of changes experimented on membrane. By ultrafiltration experiments, membranes with different cut-off (1, 10, 50 and 100 kDa) were fouled using aqueous extracts of plant leaves (P. alvaradoii). Surface changes of membranes were analyzed by attenuated total reflectance, permeability analysis and image analysis. Results evidence the applicability of surface color index (I) for the description of fouling and membrane surface changes. In addition, results suggest that image analysis using color-based quantitative descriptors can be used to description of surface anisotropy of membranes and easily correlated with permeability and fouling layer thickness. (C) 2016 Elsevier B.V. All rights reserved.