"Zoo Quest" in colour. Why colour for black-and-white television?

Those who saw the recent BBC programme after the discovery that the original footage of "Zoo Quest" from the 1950s was filmed in colour will have been amazed by its quality and by the skill of Charles Lagus, the cinematographer. Nearly twenty years before the appearance of colour television in U.K. the technical people at the BBC insisted on the use of colour negative film rather than black-and-white film for the clockwork-driven 16 mm camera. Sir David Attenborough explained that the BBC only agreed to 16 mm, necessary for portability in the field, after a huge row. 16 mm was for amateurs: professionals used 35 mm. The reason why Charles Lagus was chosen was because he had experience of using 16 mm equipment (technical films which would be projected for relatively small audiences were filmed in 16 mm because the equipment and film was much cheaper).

What was not explained in the programme was the reason why colour negative film was insisted upon. I can only assume that it was less grainy than the black and white negative stock available at the time with the silver grains having been washed out during processing to leave the dyes. If that were the case then colour positive stock would have been the alternative. However, the exposure latitude of colour negative was, and still is, much greater than colour positive film. That would have been an asset in the field where it would be difficult to get the exact exposure that postive film demands.

It would appear that only black-and-white prints were taken from the original footage since neither the presenter nor the cinematographer could remember that it had ever been in colour. In what form it was televised I do not know but printing from a colour negative with relatively wide latitude would have enabled contrast to have been controlled at the printing stage and the use of slow, fine-grain black-and-white material.

The advantage in terms of quality of output of using colour negative film stock would have been offset by their lack of speed. Colour films were then incredibly slow by modern standards (about 10-20 ASA). Indeed there were situations, when the Komodo Dragon was lured into a trap, for example, when a faster black-and-white film had to be used just to get a shot. The quality was noticeably lower.

You can also see from the footage another advantage of using 16 mm rather than 35 mm film for wildlife—the greater depth of field.

I have not been able to find what colour negative film Charles Lagus was told to use. The BJP Almanacs for the early 1950s list only 16 mm positive films. However, I have read that the BBC worked with Kodak in the 1950s and 60s to bring 16 mm cinematography to a professional level (i.e. to replace 35 mm for television use) so my guess is the film was Kodak but which one I have not been able to work out.