Efficacy of USB microscopes for imaging forensic materials.

USB microscopy, a relatively new and developing technology, offers a highly portable and relatively inexpensive means for performing microscopy. However, it has not been established that USB microscopes are capable of imaging at a level deemed sufficient for forensic requirements. The purpose of this study was to determine the value, applicability, and limitations of current USB microscope technology by comparing USB microscopes with traditional microscopes by collecting images of common forensic trace materials. For our tests, we considered image clarity, resolution, magnification, field of view, working distance, ease of use, and reflected versus transmission mode imaging. The USB microscopes were highly portable, easy to work with, and able to take an image in any orientation. They also demonstrated a strong sensitivity to different hues of color and were easily tailored to different forms of microscopy by utilizing additional optical components. USB microscopes do not share the same level of resolution, image quality, or image contrast as the most sophisticated microscopes. However, USB microscopes could add value to forensic investigations when used for preliminary exams, low magnification imaging of samples, and imaging scenarios that require magnification but don't conform to traditional microscopy.