Like so many BBC programmes made around 1971 on 2" Ampex Quad video tape in 625 PAL, some episodes have been wiped. Unlike the Jon Pertwee Doctor Who episodes from this time I do not believe any of the wiped Doomwatch episodes have any Black & White 16mm film copies in the archive to support them, if someone can prove me wrong please do.
I have seen the episodes that were shown on UKGold. From Season 1 my favourite episodes are 'The Devil's Sweets', 'Train and De-Train' and 'The Battery people' which are very good indeed. I also have a direct from the 2" Quad to S-VHS copy of 'Sex and Violence' with VT clock at the start and the studio material in place after the end credits. The originally untransmitted episode 5 is a very interesting glimps on views from this period in time. The studio material that exists at the end of the 2" Quad Tape is also interesting to me as I love watching early BBC studio material.
BBC4 Repeat of Tomorrow, the Rat
Now if I recall correctly, Tomorrow, the Rat was one of the first to have James Insell's Reverse Standards Conversion or RSC process applied to it shortly after it had been used to return Doctor Who - 'The Claws of Axos' back to 625 PAL format.
Just like 'The Claws of Axos' episodes the NTSC tapes for the surviving Doomwatch episode 'Tomorrow the Rat' had originally been produced by the BBC in the mid-seventies using the BBC-designed CO6/508 Advanced Field-Store Converter (or BBC MK2B Standards Converter, as it was officially known - its sister, the MK2A, worked the opposite way, converting NTSC to PAL), an enormous and highly complicated standards converter which was used to convert the 625-line, 50 field-per second PAL video into 525-line, 60 field per-second NTSC video. To do this, it produced NTSC fields which were either down-sampled 625-line fields, or were a mix of two down-sampled 625-line fields. So there was a characteristic juddering of any moving object or any camera pans on the conversion, which was burnt-in to the NTSC video.
The completed RSC process results were then broadcast on BBC4, however I seem to recall James was not happpy after since he had left instructions in the broadcast digital master tape box for a level of video noise reduction to be used that was not done. This had the result of the broadcast been reduced in quality to what James had expected for the work completed by the developed team led by James.
With thanks to Robert Manners on the Doctor Who Forum at www.planetmondas.com