Description in scriptwriting is an incredibly powerful tool to set vivid images in the visualization of a reader’s mind—moving them right into the world that the story unfolds. Through carefully chosen words and phrases stimulating the senses, detail, and richness for the settings, characters, and emotions are able to be expressed by the writer.
Descriptive language can include descriptions not only of visual elements such as colors, shapes, and textures but also those of sounds and voices, touches, and smells. This language is very effective for atmosphere, establishment of mood, and setting the tone in a scene, while it gives proper direction to the audience’s imagination and elicits the right kind of emotional responses.
Be it landscapes—shot locations of a fantasy world—or detailed portraits of the inner turmoil of a character, descriptive language is what makes for effective visual storytelling while scriptwriting.
TED-Ed has this interesting video where Nalo Hopkinson explains about “How to write descriptively”