Printed Fingerprints: A Framework and first results towards detection of artificially printed latent fingerprints for forensics Stefan Kiltz a , Mario Hildebrandt a , Jana Dittmann a , Claus Vielhauer b , Christian Kraetzer a a Research Group on Multimedia and Security, Dept. of Computer Science, Otto-von-Guericke University, PO Box 4120, 39016 Magdeburg, Germany; b Brandenburg University of Applied Sciences, PSF 2132, 14737 Brandenburg, Germany ABSTRACT In Schwarz 1 an amino acid model for printing latent fingerprints to porous surfaces is introduced, motivated by the need for reproducibility tests of different development techniques for forensic investigations. However, this technique also enables the fabrication of artificial traces constituting a possible threat to security, motivating a need for research of appropriate detection techniques. In this paper a new framework for modelling the properties of a generic fingerprint examination process is introduced. Based on the framework, examination properties and detection properties are derived by a subjective evaluation. We suggest a first formalisation of exemplary properties, which can be easily extended to fit different needs. We present a first experimental setup limited to two printers and the Schwarz amino acid model using absorbing and non-absorbing material with first results to show tendencies and underline the necessity for further research. Keywords: Subjective quality evaluation, multimedia systems evaluations 1. MOTIVATION In Schwarz 1 an amino acid model for printing latent fingerprints to porous surfaces is introduced. This is motivated by the need for reproducibility during the assessment of different development techniques for forensic investigations. Those amino acids are printed on paper in different concentrations by means of a HP bubble-jet ink-jet printer. This approach can be used legitimately for quality assurance (according to 1 ). Besides this aspect, with an increasing amount of fingerprints addressed in today’s biometric authentication systems the miss-use of such a printing approach by enabling the fabrication of artificial traces constitutes a possible threat to security (e.g. see constitutional complaint reported in 2008 by 10 ). Thereby latent fingerprints (real, natural fingerprint patterns) can be captured without the knowledge of the person concerned, e.g. 9 where a fingerprint is taken from a glass of water. Using the Schwarz amino acid model with ink-jet printers the captured real, natural fingerprint pattern can be printed; enabling in theory the fabrication of traces of everyone on a crime scene. Hence, the detectability of artificial traces is an upcoming necessity in forensics. In our paper the following question is addressed: How to detect and distinguish between real, natural latent fingerprint patterns from humans and artificially printed latent fingerprints under the consideration of the Schwarz amino acid model and bubble- jet printing techniques (from 1 ). The potentially relevant properties of existing printing technologies, fingerprint properties and existing optical scan technologies are briefly described in section 2. Based on the findings of section 2 we address the problem of detecting artificially printed latent fingerprints by suggesting a new framework for modelling the properties of a generic fingerprint examination process in section 3. The framework formalises the examination as a process chain composed of the fingerprint printing, processing of the physical forensic trace sample, digital acquisition and a later subsequent subjective assessment of the digital sample. Based on this framework we experimentally study, using the test setup described in section 4, which of the properties are significant for detection. For this purpose, we present our first results from experiments in using samples from two different printers, which printed one fingerprint on two different printing surfaces and optionally applied development techniques:  Using the Schwarz amino acid ink only,  Enhanced by the development technique ninhydrin or  Enhanced by the development technique carbon black powdering Image Quality and System Performance VIII, edited by Susan P. Farnand, Frans Gaykema, Proc. of SPIE-IS&T Electronic Imaging, SPIE Vol. 7867, 78670U · © 2011 SPIE-IS&T · CCC code: 0277-786X/11/$18 · doi: 10.1117/12.872329 SPIE-IS&T/ Vol. 7867 78670U-1