A "high-performance" 2D gel scanner

We describe the design principles of a photometric flatbed scanner with a scan area of 250 X 250 mm2, a dynamic range of 4000 gray levels, a signal/noise ratio of 2000/1, a step size of 0.1 mm, and a step frequency of 2000 steps per second. It is controlled by a microcomputer and used to acquire data for quantitative evaluation of gels or chromatograms. The performance of the instrument is demonstrated by the data obtained by scanning gratings, gray step filters, and high-resolution electropherograms.