Subtitling is a type of audiovisual translation that has its own specifications, rules and criteria. The first thing to do before exploring the world of subtitling is to understand that this type of translation belongs to “subordinate translation”. Thus, it is a translation that has restrictions of time and space which directly affect the final result. Our translation depends on these parameters and it does not only consist of translating the textual context, but also supporting us in the image and the audio, with determined time and space.
The space which we have in our translation is limited to 2 lines of subtitles which are usually placed and generally centred at the bottom of the screen. Each line cannot contain more than 35 characters (i.e. any letter, symbol or space). The subtitle (formed by 2 lines) can have up to 70 characters.
In terms of the limits of time, a subtitle has a minimum duration of a second and a maximum duration of 6 seconds on screen.
But, there is a direct relation between the duration of a subtitle and the number of characters that it can contain so that it can be read. These parameters are based on an average reading speed. We cannot read the same amount of text if we have 6 seconds or less. It is estimated that the current average reading speed is 3 words a second. So to read a complete subtitle of 2 lines and 70 characters, we will need at least 4 seconds, which house some 12 words. If we have less time, we must calculate less characters.