[Characterization of microtraces of blood]

The stains produced from micro-blood-drops (blood volume 0.2 microliter) on different substrate materials were examined with respect to morphological characteristics. Micro-stains made on paper showed the same general pattern as larger (macro-)bloodstains on the same substrate. The use of shirt material as substrate, however, resulted in differences in the stain pattern, particularly a greater variation within otherwise identical series. In addition when the angle of the bloodstains was acute, a variable number of smaller stains became detached. In these cases definite criteria can still be found for a description of bloodstains and for estimating the approximate angle of impact.