This paper presents a study of the optical properties, microstructure and chemical composition of titanium oxide layers deposited on Ti film using gas injection magnetron sputtering (GIMS). The samples are examined by means of spectroscopic ellipsometry, atomic force microscopy and X-ray photoelectron spectroscopy. The investigation is complemented by colorimetric measurements. The influence of deposition time on the thickness of dielectric layers has been found. A comprehensive analysis of effective dielectric functions of titanium and titanium oxide films is presented. The thickness of titanium oxide film ranges from 13 nm to 54 nm and directly determines the colour of a sample from gold to blue, respectively. (C) 2014 Elsevier B.V. All rights reserved.