The work reported in this paper questions the relevance of using fractal concept to study liquid primary atomization process by characterizing the shape of the continuous liquid flow from the nozzle exit to the end of the atornization process. First, three fractal methods were tested on synthetic images in order to define the best adapted protocol to the objective of the study. It appeared that the Euclidean distance mapping was the best appropriate method. Second, this technique was applied to analyze series of images of atomizing liquid flows obtained for several working conditions. This application demonstrates that atomizing liquid flows are fractal objects and that primary atornization can be reasonably seen as fractal processes. The appropriateness of fractal concept was also demonstrated by the fact that fractal characteristics such as textural or structural fractal dimension and inner cutoff scale are physically representative of the process investigated here. (C) 2007 Elsevier Ltd. All rights reserved.