Within the frame of this work, coloured films based on single layered titanium oxynitride (TiNxOy) compounds were prepared. The films were deposited by r.f. magnetron sputtering under variation of process parameters such as bias voltage and flow rate of reactive gases. Colour varied from shiny golden type for low oxygen contents (characteristic of TiN films) to dark blue for higher oxygen contents. The information on the composition was obtained by Rutherford backscattering spectrometry. X-ray diffraction results revealed the development of a face-centred cubic phase with <1 1 1> orientation (TiN type; lattice parameter of similar to0.429 nm) and traces of dispersed oxide phases. Nanoindentation experiments showed values of hardness between 20 and 40 GPa, strongly dependent on the composition and microstructure. Compressive stresses between -0.5 and -6 GPa were determined by the deflection method. (C) 2003 Elsevier Science B.V. All rights reserved.