What is a Flashback?

A flashback according to Wikipedia is, "the interruption of a narrative by the interpolation chronological sequence of events that occurred previously." It is therefore a form of anachronism.

When we tell a story, it usually follows a natural time sequence - the events are narrated in the order of occurrence. When, in the middle of this sequence, we introduce a scene that occurred before that time we call it a flashback scene.

Introducing a little more theory, a flashback could be "internal" (refers to an earlier time but still within the narrative) or "external" (refers to a time prior to the beginning of the narrative).

Flashbacks usually occur in the narrative in response to a stimulus. For example, one character sees or hears something that brings to mind a past event. Juno looks at an abandoned chair and recalls the afternoon he made love with his best friend; Rose sees the sketch and recalls the night she spent with Jack.

In the first example (the film "Juno"), a visual stimulus (could be auditory, olfactory, sensory, etc.) introduces a quick flashback scene. The narrative then returns to its normal course. This is perhaps the most common form.

In the second example (the film "Titanic"), the story begins in the present, but after Rose's character, now elderly, gets confronted with the testimonies of its past, enters into a long flashback that tells the essential story and thus becomes a natural narrative sequence.

Some writers such as Guillermo Arriaga and James Cameron use so many flashbacks and flash-forwards in their writing that at some point a natural narrative simply ceases to exist. This is termed as anachronistic narrative.

When to avoid the use of flashback?

Some screenwriters are averse to the use of flashbacks, but it's mostly because of the misuse of this technique, rather than a drawback of the resource itself. Such misuse often happens when the flashback is used simply to transmit information needed to solve some aspect of the narrative. In this case, as in any other purely expository scene, the flashback is used as a crutch and reveals the laziness of the author. Flashbacks should not used to plug loopholes in the narrative.

Flashback format

Writing a flashback is no big deal. Apply exactly the same rules as you'd for any other scene. In short, we should only write what can be shown (visually) or heard (auditory) in the film. No use writing thoughts, emotions, hopes or other things that do not have a visual or audible translation. Only actions, gestures, words and expressions which can be narrated using the resources of the cinema should be included.