A 2D-tomographic reconstruction of Da - and C III emission distribution in L-mode density limit discharge has been performed using the Singular Value Decomposition method. Significant differences were observed in line emission between inner and outer divertor: at low central electron density (2¥1019 m-3), the maximum of the hydrogen radiation is located near the target plates at the position of the strike zone but with significantly more radiation from the inner leg than from the outer. The C III-radiation, on the other hand, is much stronger in the outer divertor, with a strong contribution near the X-point. With increasing density, Da extends two-dimensionally within the inner divertor and, at the same time, the Da radiation increases in the outer divertor. During the density rise, a reduction of C III-emission takes place, due to a decrease of the electron temperature and, accordingly, of the physical sputtering yield. It is shown that the major contributor to Da emission, under the observed conditions, lies in excitation processes and that low-energy charge-exchange reactions with neutral deuterium can influence the ionisation balance of carbon and the recorded C III-emission line. Moreover, the emission patterns obtained from different diagnostics are in good agreement. The evolution of the intrinsic hydrogen and carbon impurity profiles in L-mode discharges is discussed with respect to its dependence on the location of methane fuelling.