New techniques have been developed for analyzing, in detail, the shape and development of ink jets and drops. By using flash illumination of very short duration (ca. 20 ns), high quality, single-event digital images of jets and drops can be captured. A computer program, PEJET, has been written to automate the processing of such images and to generate quantitative data about the whole ink stream. From this data, it is then possible to compute the variation in fluid volume, volume flow, and velocity as a function of both position and time. The method has been shown to have high accuracy. The results can be used to study the influences of nozzle design, drive waveform, and fluid properties on jet and drop formation, as well as to provide accurate data for comparison to the results of computational modeling. Examples of results from a drop-on-demand system are presented that illustrate the potential of the method to compare quantitatively the performance of print systems and inks.