Art forgery is one of the most important issues of art and antiques market which can be reduced and prevented by criminal law measures. Art fakes can be detected by expert witness who applied forensic science methods. Access to specialized knowledge from three fields of science, i.e. criminal law, art history and forensic science is necessary to handle with art forgery. Therefore, the research was focused on criminal law and forensic science issues. Because expert witnesses (forensic science experts) pose a crucial role in detection of art fakes, comparative studies on access to the function of expert, use of opinion as an evidence and criminal liability of expert witnesses in criminal proceedings in Poland, Germany, France and Italy were performed. Research shows that regulations are generally similar in compared European countries, but indeed they differ in some important issues. Proper forensic expertise should consist of historical and stylistic research, signature analysis and material identification. Various spectroscopic and chromatographic methods can be used for identification and characterization of artwork materials, i.e. organic and mineral pigments, binders and varnishes. Possibilities of classification and differentiation for forensic purposes of the most popular red and brown pigments in paint layers were evaluated. Elemental analysis was performed by X-Ray Fluorescence and Laser Ablation - Inductively Coupled Plasma – Mass Spectrometry. Results shows that modern paint colors which are produced by different manufacturers differ strongly in elemental composition, including major elements. However classification of paint samples based on elemental composition is limited.