The sensitivity of the track-etch neutron radiography method, to discern thickness of materials, has been investigated. The radiographs have been obtained in a facility installed at the IEA-R1 nuclear research reactor by using the solid-state nuclear track detector Makrofol-DE. In order to minimize image distortions caused by the neutron beam angular divergence, the samples have been positioned as close as possible to the detectors. For this irradiation geometry, neutrons scattered by sample can contribute to the image formation and consequently to the method's sensitivity.