Stainless steel and chromium-electroplated metal can change their metallic surface aspects into different colours by thin film deposition technologies. In this study, the colour change of titanium carbonitride (TiC x N y ) thin films as a function of N 2 and CH 4 flow rates in the deposition process was investigated. TiC x N y thin films were deposited by cathodic arc in an industrial equipment at low temperature (125°C) for decorative purposes. The samples were analysed by X-ray diffraction, scanning electron microscopy, glow discharge optical emissions spectroscopy, nanohardness, nanoscratch test and colorimetric analysis. The colour slightly changes from yellow gold to light bronze with carbon addition in the thin film structure. Scratch test determines an increase of the critical load for both plastic deformation and delamination as the carbon content increases. The failure mode shifts from brittle/ductile mode to ductile mode with the increase of the carbon content.