Characterization is the process of using words on a page to transform a figure of the writer’s imagination into a living, breathing, whole person in the imagination of a reader.
Exposition = Narrative Summary
In the context of characterization, exposition is a comprehensive explanation of a character, consisting of a list of physical attributes, historical background, psychological profile, or a combination of some or all of these elements.
Exposition can be very boring, especially when used in characterization. It’s important to remember that it is not necessary for the reader to know all these little details in order for the character to form in their head. In fact, long, listing descriptions can be too much to digest all at once. Readers may be tempted to skim through or completely skip long, expository blocks of text in order to stay engaged with the story. It is better to show who the character is through his or her actions and dialogue rather than telling everything up front.
In most cases, narrative summary should only be used as a transition to get the reader from one scene to the next. The writer should only supply relevant details as they are necessary to move the story forward.
Just because you, as the writer, may need to know your protagonist’s every little quirk and historical detail to be able to write the character, that does not mean you need to share all of those details with your reader. Instead, each detail should earn its way into the story.
Leaving room for your writer’s intuition to grow your character organically over the course of time allows the reader to get to know the character organically as well. Sometimes it’s better to allow the reader to reach his own conclusions based on your character’s actions and speech rather than drawing the conclusions out for them explicitly.
You should also avoid using the standard tropes for describing characters such as having a character look in a mirror and describe herself. Let’s get real here. How often have you stood in front of a mirror and described yourself to yourself? I mean, do people even do that in real life? It’s just not a very authentic ruse.
Avoid using too many flashback scenes to show where a character is coming from. Try to keep your readers firmly rooted in your current story most of the time. Flashback scenes must also earn their presence in your story. And avoid letting your characters speak just for the sake of explaining a concept to your readers.
Exposition can also apply to other details, such as history and background info (backstory), not just as it relates to characterization. As with characterization, you should only give your readers what they need in the moment to move forward with the story.