Masking
Masking cinematography uses a matte, a viewfinder object, or a graphic window so looking is visible as a shape cutting the picture. We see through binoculars, a keyhole, or a hard-edged hole.
Narrative function
The audience is made to look as a character looks. A circle of night, a door slot, a camera's own frame-lines.
The surround is black or graphic. The photograph lives only in the hole.
It is the wrong tool when you merely want a tighter shot, or when the container itself should widen. If the outer bounds of the movie change ratio, that is a ratio switch.
If a doorway is simply in the set, that is a frame within a frame.
How it works
Put a physical mask in front of the lens (binoculars, a cutout, an iris board) or add a hard matte in optical printing. The interior of the hole is the exposure.
The surround stays opaque. Keep the subject composed for that shape, not for the full sensor.
Light the interior as a real scene. The mask does not need its own key.
Prompt a masked frame around the subject: a shape cutting the picture, binoculars, a keyhole, a graphic window.
When to use it
Use it for the beat of spying, peeping, or a title that looks through an object. Do not use it as a fancy crop on a scene that is not about looking.
Compared with similar shots
Frame within Frame uses architecture already in the room: a window, a door, a mirror. Masking cuts the picture with a shape that is the act of looking.
Iris opens or closes a circle as a transition. A masked binocular hole can sit for the whole shot.
In film
Kill Bill looks through coffin slots and tight graphic holes. The Grand Budapest Hotel boxes looking as a designed window.
Grammar for seeing-as-object, not frames to copy.
Prompt it
Masked frame around [Subject], a shape cutting the picture, binoculars, a keyhole, a graphic window. Name the shape, keep the interior photographed, and keep the surround opaque.
Do not stretch the image to fill the hole.
What usually goes wrong
The usual wrong cousins are a Wide Shot with a vignette, or a Ratio Switch. The tell is a soft dark edge, or the whole frame widening.
The fix is a hard shape, a hole, and a scene composed for that hole.
Questions
What is masking in film?
Masking cuts the picture with a shape so looking is visible as an object: binoculars, a keyhole, a graphic window. The photograph lives inside the hole.
Masking vs iris
An iris is usually a circular transition that opens or closes. Masking is a persistent shape through which we look. One is a join. The other is a viewfinder.
When should I use masking?
Use it when the act of looking should be an object in the shot. Skip it when you only need a closer framing or a change of aspect ratio.
How do I prompt masking for AI image or video?
Write Masked frame around [Subject], a shape cutting the picture. Name binoculars, a keyhole, or a graphic window. Keep the surround opaque and the interior a real photograph.
Melies can generate this Masking
Melies is the AI filmmaking workspace. This Masking opens with the optical prompt loaded, so the effect has a physical cause in the frame.