Editing Light characteristic (section)

===Flashing light===
{{Redirect|Flashing light|other uses|Flashing Lights (disambiguation)}}
A flashing light is a rhythmic light in which the total duration of the light in each period is clearly shorter than the total duration of the darkness and in which the flashes of light are all of equal duration. It is most commonly used for a single-flashing light which exhibits only single flashes which are repeated at regular intervals, in which case it is abbreviated simply as "Fl". It can also be used with a group of flashes which are regularly repeated, in which case the abbreviation is "Fl(2)" or "Gr Fl(2)", for a group of two flashes. Another possibility is a composite group, in which successive groups in the period have different numbers of flashes, e.g. "Fl. (2+1)" indicates a group of two flashes, followed by one flash.

A specific case sometimes used<ref name=LoL/> is when the flashes are longer than two seconds. Such a light is sometimes denoted "long flashing" with the abbreviation "L.Fl".

If the frequency of flashes is high (more than 30<ref name=LLQuick>''Light List'' states at one point that only "frequency not exceeding 30 flashes per minute" is considered "Flashing", yet at another that only "a rate of 60 flashes per minute" is considered "Quick", leaving the interval in-between undefined.</ref> or 50<ref name=LoL>''List of Lights''</ref> per minute) the light is denoted as a "quick light", see below.