Film is a visual medium. This sounds obvious, but the implications for how you write a screenplay are profound.
Everything in your screenplay must be visible. So many times, I've seen scripts 'telling' people's internal states; how they feel, what they're thinking. None of this can be captured directly and, worse, actors don't like to be told these things. If the camera can't capture it, it can't be in your script.
The camera is your narrator
In prose, you have access to everything. Thoughts, feelings, history, future. You can tell the reader what things mean, how to feel, what to think.
In screenwriting, the camera is your only narrator — and the camera can only see surfaces. Actions. Expressions. Objects. Movement.
Your job is to choose which surfaces reveal the depths.
Showing internal states
Characters have internal lives. They feel things. How do you convey that when you can't describe it? They can only do this through action. 'Looking moody' is not an action. It's inaction. But a character visiting a mournful looking place on a rainy day, or repeating an action on their own they did with someone before? Now we're talking.
Behaviour
What does someone do when they're nervous? Tap their foot. Check their phone repeatedly. Smooth their clothes. And what does it say when, once you've established something, they stop or change?
Objects
What a character holds, looks at, interacts with. A woman clutching her dead husband's watch tells us something no dialogue could. Objects often serve as useful signposts – how they're used in different ways, or dropped.
Environment
How does the space reflect the character? A meticulously organised desk. A chaotic apartment. These aren't just settings — they're character revelation.
Contrast
What's the gap between what a character says and what they do? That gap is where meaning lives.
The power of the cut
Editing creates meaning through juxtaposition. Image A followed by Image B implies a relationship. Our brains are wired to seek meaning, which is why film is such a powerful medium. It invites the viewer to construct the story in their head as you go along.
A character says "I would never lie to you." Cut to their hand, crumpling a letter. We understand without being told.
When you write with cuts in mind — when you think about what follows what — you're doing some of the editor's work on the page. You're building meaning through sequence.
Details matter
When you write "John's hand trembles as he reaches for the envelope," you're asking for a close-up. You're saying: this matters. Look here.
Choose your details carefully. Not every moment needs emphasis. But the moments that do should be isolated, given space, made visible.
An exercise
Think of a complex internal state. Guilt. Anticipation. Hidden attraction. Regret.
Now write a short scene — no dialogue — that conveys that state purely through visible action. What does the character do? What do they look at? What small gesture reveals everything?
This is the essence of screenwriting. Making the invisible visible, one image at a time.
What you gain
This discipline — writing only what can be seen — makes you a better storyteller in every medium. You start to find the concrete, specific detail that embodies the abstract feeling. You learn to trust images instead of explanations.
Even if you never write another screenplay, the skill transfers. And if you do write screenplays, it's the fundamental skill you need.