Subtitles and closed captioning best practices
First, let us remind you that subtitles and captions are not the same: they may or may not be interchangeable; it depends on numerous factors. Moreover, subtitles can be open (embedded in the movie) or closed (a separate file). But in our case, it doesn’t matter, as their positioning and other features are more or less the same.
Each country and even each company has its own recommendations. Subtitles for breaking news will differ from those for a movie, especially if we deal with different continents.
Nevertheless, there is a recommended set of practices that make your subtitles clear and comprehensive for every viewer. These rules are not strict, but they may give you a general idea on the best practices of closed captioning.
The best subtitles font is with no serifs, like Helvetica, Arial, Roboto, Verdana, etc. Font for captions must be neutral, as it shouldn’t attract any additional attention.
There are no common recommendations, as the size depends on the video’s resolution and other factors. Subtitles must be large enough to read them from a distance but small enough not to cover more than 1/12 part of the screen.
The best practice is to place white subtitles against a transparent grayish background. Make sure the color is neither too bright nor too pale.
Usually, captions are placed in the lower part of the screen to not interfere with the action on the monitor. They should take two lines as a maximum, each line no longer than 35-42 characters. Subtitles must be shown accordingly with the speech of the actors, if the sentence is shorter than 35 symbols, it should be centered.
An average reader’s speed is about three words per second, so two 40-character lines (~14 words) should remain on the screen for no less than 5 seconds. Single-line captions need about 3 seconds accordingly.
Now, when you know general recommendations, you can create your captions in a free online tool. The service also allows you to edit SRT files or create subtitles and save them as a separate document.