These moments are over in an instant, but not before making an impression on an almost subliminal level. Sometimes you just have to freeze the frame to unpack the complex visual message. A train is an apt metaphor for a slow film dissolve – it moves across time, from one place to another and in the middle of the journey, you have The 3rd Shot.

It is the inevitable tendency of the audience to draw a comparison between two overlapping images, some literate connection between them. As moviegoers, we are trained to look for a narrative thread when we watch a film. From this premise many outstanding superimpositions in film have been created.

The dissolve is an editing device to show the progression of time or a character’s change in mental state. Most movie dissolves are a way to advance the story and get from here to there, and any artfulness that results is a mere by-product. 

But what about the dissolves that do more than just advance the plot? Some dissolves rise above their function and become miniature works of art themselves. The inevitable result of a slow dissolve that superimposes someone or something next to a character’s face is that the audience will get the impression that the character is remembering or imagining what is superimposed. 

The cinematic equivalent of a man watching his life flash before his eyes at the moment of death is shown in an incomparably artful way in The Great Ziegfeld when a producer of flamboyant theatrical productions is on his deathbed. To convey his near death vision of his life’s work, the image of showgirls dance across his weary face, which seems to grow heavier as they march down his visage.

The layering of images on top of one another is a uniquely photographic conceit. When a superimposition is particularly thoughtful, it can deepen the metaphors and themes of the story and give the audience information and details that add dimension to the overall film.