Calibrating the Line



The SV7510 Still Video Printer consisted primarilly of a small B&W video monitor, a lens, a place for an instant film pack and a color filter wheel with RGB filters. Circuitry took the incoming composite or RGB signal and would expose the film sequentially with RG&B light from the video monitor to create an image on the instant film. The problem arose in balancing the output of the three exposures, since the density and sensitivity of the film varied depending on which filter the light passed through.

A way to calibrate the devices to a proper color balance by an unskilled line worker was needed. Color balance could be controlled somewhat with several adjustable "pots" (potentiometers) inside the printer. Since I had experience as a darkroom color printer, I was given the task to come up with a solution. An engineer was assigned to help me with the task, I suggested we borrow the technique that my Beseler Color Computer used to determine a precise color balance, using light sensing photo diodes. The engineer, suggested using the new digital oscilloscope to measure the light output of the photo diodes on the oscilloscope graph. This worked extremely well! The digital oscilloscope could capture an exposure curve for each of the color exposures and the height of these curves could be made equal with the adjustment pots. Unfortunately, the Polaroid suit in January 1986, spelled the end for Instant products and the end of the SV7510 Still Video Color Printer as well.

Although we as a team had tried to pivot to a 35mm film version of the SV7510, marketing wouldn't support it. With the end of the SV7510 project, I was to be re-assigned to the Systems Group of Advanced Development, in what was now the Electronic Photography Division. It would turn out to be an excellent position for me.

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