Abstract: A data printing apparatus for printing alphanumeric information on photographic slide mounts includes a slide track along which the photographic slide mounts are advanced. When the slide mount is positioned at a printing station along the slide track, a movable print head prints alphanumeric characters on the slide mount. The print head is carried on a carriage, which in turn is movable on a carriage track. The carriage track is aligned in a plane parallel to a plane defined by the slide track and runs in a generally transverse direction to the slide track, so that the print head moves transversely to the longitudinal direction of the slide track as a carriage drive moves the carriage on the carriage track.

Abstract: A photographic printer includes large area transmission density (LATD) sensors and a digital processor, such as a microprocessor, which calculates red, green and blue exposure times based upon the LATD sensor readings. The LATD sensors provide analog photosignals which are a function of light received. Voltage controlled oscillators for each color channel provide red, green pulse signals which have durations which are a function of the red, green and blue analog photosignals, respectively. Red, green and blue gate circuitry receives red, green and blue enable signals from the microprocessor together with the red, green and blue pulse signals from the voltage controlled oscillators. The outputs of the gate circuitry are red, green and blue gate signals which are supplied to red, green and blue counters, respectively, and permit the counters to count in response to a high frequency clock signal. The resulting count in each counter, therefore, is a function of the duration of the gate signal which it received.