The Colour Strike was an industrial action by technicians at all ITV companies from 13 November 1970 to 8 February 1971 (although some shows made during this period in black and white were having their first transmission as late as December 1971) who, due to a pay dispute with their management, refused to work with colour television equipment.
At that time ITV had recently switched to colour transmissions, requiring the individual companies to invest heavily in new equipment. Early colour television studio cameras consisted of four tubes to relay the picture: three were receptive to colour (red, green and blue – the chrominance signal) with the fourth providing a high-resolution monochrome image (the luminance signal) which was still required as many viewers still watched on monochrome receivers. The final colour picture was created by combining the chrominance and luminance signals, but the technicians simply switched off the colour tubes whilst this dispute took place.
This meant that even though colour equipment was available, all shows were recorded and broadcast in monochrome, thus denying the ITV companies the ability to sell airtime at the higher value that colour transmissions dictated.
In some film sequences for location shots in these programmes (shot in colour), the colour signal from the telecine machine had to be switched off in the vision mixing desk before being recorded to tape, but this was partly unsuccessful, leading to some film sequences being recorded with an odd array of pale colours (as for items where the colour is a mix of two primary colours, only one primary colour would show). This is prominent in the second series of Hadleigh, for example.
The first Coronation Street to be broadcast in colour was transmitted on 3 November 1969, but due to the strike, some 1970–71 episodes, including the one featuring the death of Valerie Barlow by electrocution, were recorded in black and white. The last monochrome edition was shown on 10 February 1971.
There was also a short dispute two years later in early 1973 affecting both BBC channels and ITV as well.
Shows affected by the ITV colour strike
- Budgie (LWT) (the first four episodes of series one)
- Please Sir (LWT) (the last three episodes of series three)
- Upstairs, Downstairs (LWT) (the first half of series one was made in black and white; the first episode was later reshot in colour. The remaining black and white episodes are often not shown in overseas syndicated broadcasts)
- The Big Match (LWT)
- Timeslip (ATV)
- Doctor at Large (LWT) (the first six episodes)
- On the Buses (LWT) (the second half of series four, plus the Christmas special 1970)
- Bless This House (Thames) (the first seven episodes of series one)
- Crossroads (ATV)
- Coronation Street (Granada) (all episodes transmitted on and between Monday 16 November 1970 and Wednesday 10 February 1971. In addition, the episodes transmitted on Monday 22 and Wednesday 24 February 1971 had black and white location inserts)
- Dear Mother...Love Albert (Yorkshire) (all 6 episodes 1 to 6 of series 3)
- Hine (ATV)
- The Mind of Mr J.G. Reader (Thames) (all of series two apart from 'Man with a Strange Tattoo')
- The Trouble with You, Lilian (LWT) (all but episode one)
- Six Dates with Barker (LWT) (episode 3)
- A Family at War (Granada) (episodes 12 to 19 of series two)
- The Dickie Henderson Show (ATV)
- Mr Digby, Darling (Yorkshire) ()
- Nearest and Dearest (Granada) (episodes 2 to 8 of series five)
- Never Mind The Quality, Feel The Width (ABC/THAMES) (episodes 1, 3–4 & 7 of series five)
- Hadleigh (Yorkshire) (episodes 1, 2, 8, 9 and 13 of series two – the last five black and white episodes of that series to be made)
- Elephant's Eggs in a Rhubarb Tree (three out of six editions)
- Freewheelers (Southern) (episodes 6 to 11 and 13 of series five)
- The Benny Hill Show (Thames)
- Queenie's Castle (Yorkshire) (the last four episodes 3–6 of series one)
- Public Eye (Thames)