Master artists and photographers use the rule of thirds in regards to light and dark as well. Many of Rembrandt’s paintings use two-thirds dark and one third light to illuminate the focus of his painting.
Rather than binding the artist or photographer down, following this rule gives freedom to consider options in creating a scene, and gives more control over the mood of the finished work.
Similarly, following the structure of the three-act play helps writers and authors format their story to get the most drama from the limited pages of their story. The first act should introduce us to, and help us to fall in love with or empathize with, the story’s main character.
Each scene, like the stroke of a brush, helps illuminate character and hints to the story as a whole. If we only paint light scenes, the story will be bland and uninteresting just as a paining composed of only the lightest hues garners little interest.
If an artist uses only dark, it will overpower the composition just as too much dark in our stories will overwhelm most readers. There needs to be a blend. And, just as an artist needs years of practice to become a master, it takes years of practice for an author to write something truly memorable.
Stroke by stroke, sentence by sentence, we build the first act, go through the first plot point, and enter act two. In a painting, this might be considered the medium hues. The strokes, neither ecstatic nor morose, that binds the story together. Then, the “black moment” when all seems lost, adds depth and emotion in order to make the story complete. In using the artist’s rule of thirds in our writing, we should add a variety of light and dark, which brings full color to our stories though depth of character and a wide variety of feelings.