BBC2 Colour Testcard F

Test Card F, designed by BBC engineer, George Hersee, was introduced in 1967, and aired on the new colour 625-line BBC Two service. The test card features Mr Hersee's daughter, Carole, pictured alongside Bubbles the clown. Test Card F was broadcast from a 35mm slide, using a Rank Cintel slide scanner. It was actually a dual-layer slide – one layer for the monochrome areas, the other for the colour parts – very carefully aligned and sealed in a glass slide-holder. There was no BBC One-branded slide version of Test Card F – the 'BBC2 COLOUR' test card slide was used on BBC One and BBC Two. However, when Test Card F was aired on BBC One, a 'BBC 1' caption was electronically-superimposed, covering up the 'BBC 2 COLOUR' legend. The Rank Cintel slide scanner was a large and expensive piece of equipment, but probably of more importance, technically, is that it would be near impossible to keep two scanners aligned identically to match each other. Like all standards, their absolute accuracy is not as important as the fact that everybody agrees. Hence, it was far better to use just one scanner, and overlay a 'BBC1' caption on the feed that was used for the BBC One transmissions, as this resulted in a consistent test signal for both networks. Test Card F was generally broadcast for longer periods during daytime hours on BBC Two than on BBC One the latter's schedule often being filled by programmes for schools and children. The BBC One caption overlay was a little crude by modern standards. It was produced by a dedicated unit that had the relevant parts from an 'Anchor' machine (an early form of electronic caption generator, before the introduction of Astons and Ryleys).