Laboratory-built systems for electronic scanning using digital cameras of varying sophistication have been described [53,77,78].These systems consist of some combination of a computer with video digitizer, light source, monochromator, and appropriate optics to illuminate the plate and focus the image onto a charged-coupled device (CCD). The plate is illuminated with monochromatic light and the reflected light focused as a scaled image of the plate directly onto the active element of the CCD camera. Commercially available systems are less versatile than some of the laboratory-built systems and consist of an illumination unit and a digital camera, for example Fig. 20.