Baird "Intermediate Film" apparatus undergoing tests at the Crystal Palace facility (note characteristic windows!)

The "intermediate film" process was resorted to in the mid-1930's as the Baird company raced against EMI for the approval of the BBC. A higher definition standard was needed for the source images, and the Baird company had not yet been able to fully utilize Farnsworth's Image Dissector camera tube, to which they had access. In the interim, in order to generate a high-quality scannable image in natural light, the intermediate film system was devised; it was based on Baird's earlier work on transferring film into television images.  An ordinary cinema camera shot the initial pictures on 17.5 mm film, which was immediately plunged into a developer tank, developed, and then scanned for broadcast (the process, amazingly, created only a one-minute delay).  Unfortunately, the Baird system eventually lost out to EMI's, and within a few weeks of the decision, the Baird facilities at the Crystal Palace were severly damaged in the fire that destroyed the building.  Only the South Tower, which housed transmitting equipment, survived.

Comments or questions to: Russell A. Potter,