In the first experiment reported in this paper we used 20
experienced latent fingerprint examiners, to investigate whether
the presence of a comparison ‘target’ print would affect the
characteristics they observe in the latent mark. Each of the 20
experts received ten stimuli: five latent marks by themselves (solo
condition) and five latent marks with the matching target print
(pair condition). All the participants were instructed identically,
requiring them to examine the latent marks and to count all the
minutiae present in the image. The experimental conditions were
counterbalanced across participants using a Latin Square design to
minimize any affects due to the order of presenting the
experimental trials [33].