Film Recording
Before VT came Film Recording (FR). Bob Oakley records the rise and fall of FR in Tel Rec. (Mouseover coloured text for more information)

The original television film recorder was an adaptation of the German Mechau projector and installed at AP. The film ran at a continuous steady speed and the picture on the CRT was reflected by mirrors and focussed on the film. The eight tilting mirrors needed very careful and frequent adjustment.
Some early installations are shown in the Archive section of this site and are detailed at Arthur Dungate’s website

Lime Grove installations operational in 1962
At this time the only operational studios at Television Centre were TC2 (producing the soap ‘Compact’), TC3 and TC4 (main productions e.g. ‘Z Cars’ shown live and recorded on 16mm.) and TC5 making Schools programmes plus ‘Pres A’ for in-shot announcers and the weather. The sources were fed from Area 80 TC Area 80 was the main VT area in the Basement. The lines to Lime Grove appeared on the bays in VT Control. on TRA, TRB, TRC and, later, TRD. At the end of the day at LG the LT (Line Termination)The VT area in Lime Grove was originally fed via the LT Room and any mis-plugging by the VT staff could cause serious (and loud!) repercussions in LG FR. room’s power was turned off. Unfortunately, the engineer did not always check that recordings had finished, especially in the more isolated FR6. The effect of a dying DA on the recorded picture was distinctive, and sometimes suggested that the logged explanation for the loss of a recording was not quite the whole story.
FR
FR2 This equipment had originally operated as a suppressed field system, where the camera pulled down the 35mm. film during one field and recorded only the next. In the mid 1950s, the CRT display was changed to a very long persistence version which displayed an orange picture. The overall brightness was modulated to produce an even exposure on the film. In common with all these systems, a vertical spot wobble would be applied to minimise the visible line structure.
As the 405 line picture rate was, at the time, locked to mains frequency, the camera was driven by a three phase mains driven motor. A large steering wheel on the side moved the stator with respect to the rotor to phase the camera shutter to the vertical interval. The relationship was monitored on a Cossor oscilloscope.

Both cameras had an associated Sepmag sound recorder.
1000 feet reels of Tri-X film were used, each lasting 10 minutes. This allowed just enough tim
e to reload a camera while the second one was in use. It was manned by four people, allocated as in FR3 below.


FR3
FR3 This comprised three ‘Rapid Pull Down’ 35mm Moy cameras with associated Sepmag sound recorders. These did not need to run locked to mains frequency as they had Thyratron valve drives. Both fields were recorded, but the first 36 lines (405 system) of each field were stored in the green medium persistence phosphor while the film was pulled down. The exposure was compensated for by a shaped neutral density filter attached to the front of the CRT. The gap between the CRT face and the filter was filled with glycerine, having about the same refractive index as glass. This was a messy process and demanded the avoidance of any air bubbles or leaks.
FR3
Sign
FR3 Camera 2 taken in 1965. The operational checklist on the right is just readable (see enlargement right). This camera had been used in the early episodes of Dr. Who.
Wedge

Photograph of a ND filter. Note the thinner section towards the bottom used to equalise the exposure before the shutter closes. This filter was found when clearing out an ‘inner ring’ store in the late 1980s.
Close examination of such a recording may exhibit a horizontal line(s) where the shutter does not synchronise precisely with the scan reaching the filter angle change at about 36 lines down from the top.
The 2000 feet reels of Pan F film lasted 20 minutes. Only two of the cameras would normally be used for a recording session. Lengths of unexposed panchromatic film which were less than 100 feet were useless for recording, but went a very long way in a still camera!