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How does a flashing light differ from an occulting light at a lighthouse?

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In coastal navigation, the distinction between a flashing light and an occulting light lies in the duration of the light versus the darkness during their respective cycles.1

Flashing Light: This signal is characterized by a light that is off for longer than it is on. It displays a single flash or a group of flashes at regular intervals, with the duration of the light being shorter than the duration of the darkness.1
Occulting Light: This signal is characterized by a light that is on for longer than it is off. The light is normally on and is momentarily interrupted by short eclipses of darkness.21

Both types of lights are used to provide a unique identification signal for mariners, with the specific pattern of flashes or eclipses known as the character of the light. These standards are regulated by the International Association of Marine Aids to Navigation and Lighthouse Authorities to ensure consistency for shipping and harbor safety.1