Subtitling
Subtitling (closed captioning) is common in many countries, but the methods of implementation vary. In the UK on analogue television the subtitles are available on channel 888 of teletext in 4 lines of up to 36 characters per line. The text is displayed at less than 140 words per minute which can mean that the dialogue is shortened. On analogue television the typeface is a mosaic one, but on digital terrestrial television the Tiresias Screenfont is used, a typeface especially designed for legibility in the TV application.
All digital TV receivers and set top boxes in the UK provide for the display of subtitling. It is advisable to choose a receiver where the subtitle service can be selected directly from a dedicated button on the remote control, rather than via a menu system.
Ofcom recommendations for the presentation of subtitles include:
- Subtitling should use the Tiresias Screenfont.
- Subtitles on standard definition DTT services should be no less than 20 television lines for the capital letter ‘V’.
- Subtitles should be placed within the ‘safe caption area’ of a 14:9 display and should normally occupy the bottom of the screen, except where they would obscure the speaker’s mouth or other vital information or activity.
- Pre-prepared block subtitles should be used for pre-recorded programmes.
- Recommended colours are white, yellow, cyan and green against a solid black background to provide the best contrast.
- The rate of subtitling should be as close as possible to the rate of the spoken text whilst allowing for adequate reading time.
- Subtitles should normally comprise a single sentence occupying no more than two lines, unless three lines will not obscure the picture. Line breaks within a word must be avoided.
- In addition to speech, subtitles should clearly describe relevant non-speech information, such as the mood of any music playing and the words of songs if possible, using the # sign to precede and conclude music.
- Where the source of speech is not immediately apparent, the first subtitle should have a caption to label the source.
- Different colours should be used to denote different speakers.
- The aim should be to synchronise speech and subtitling as closely as possible. Subtitle appearance should coincide with speech onset and disappearance should coincide roughly with the end of the corresponding speech segment.
- The speed should not normally exceed 160 to 180 words per minutes for pre-recorded programmes. Slower speed and more heavily edited subtitles are appropriate for young children.
- The word ‘Subtitles’ should be displayed legibly on the screen at the start of the programme.
Last updated: 20.11.2009 © Copyright reserved Website design: Digital Accessibility Team