The stability of fuel oils could be affected by sediments and sludge, which may block filters and lines in the feeding pipes and engines. The development of a reliable method for the fuel oil stability assessment is still a hot topic. The presented method is based on the Spot test according to ASTM D 4740 but the spot is visualized, modified by software and converted into RGB histograms. The histograms provide the parameters necessary for the calculation of the V-value. This parameter was effectively correlated with the frequently used Total Sediment Accelerated and with other properties for the evaluation of the fuel oil quality and stability.