Overview
"Open Matte" (literally "opened matte") refers not to equipment or grip gear, but to a shooting and distribution technique. A film is exposed on a negative with an almost square aspect ratio (full aperture or Academy format). For theatrical distribution, the image is cropped at the top and bottom by a matte to the desired widescreen format. If this matte is removed for later distribution – classically for 4:3 television or home video – the image "opens" at the top and bottom, revealing more image height than the theatrical version. This is precisely what an open-matte version is.
Unlike pan-and-scan, which crops the image edges left and right to force widescreen material into a more square format, open matte adds unseen image material at the top and bottom. The technique is closely linked to "soft matte" exposure: the camera records the entire image field, and the final widescreen image boundary is only created by a matte in projection or post-production (as opposed to "hard matte," where the matte is already fixed within the image).
Involved Aspect Ratios
| Format | Aspect Ratio | Role |
|---|
| Silent Aperture (Full Frame) | 1.33:1 | exposed negative area / open matte |
| Academy | 1.37:1 | scan basis for many open-matte versions |
| Cinematic Widescreen | 1.66:1 / 1.85:1 | matted theatrical version |
| 16:9 TV | 1.78:1 | common distribution format |
Note: The exact ratios depend on the specific negative and distribution format; in Super 35 productions, open matte is often combined with pan-and-scan because visual effects shots were rendered in a wider format and cannot be easily opened up.
Relevance for Lighting and Grip
For set work, open matte is primarily relevant as a warning: the area above and below the visible theatrical image boundary is also exposed on the negative. What is set up within the "protected" matte area can suddenly become visible in an open-matte version – typically boom poles, microphone booms, stands, cables, top lights, or set edges. Anyone composing for widescreen must therefore know if an unmatted version is planned ("protect for open matte"): in this case, the entire exposed frame must remain clean, not just the theatrical image crop.
Viewfinders and monitors usually display the boundary via superimposed guidelines (frame lines / safe areas) for the cinematic format. However, when "cleaning" the image, lighting and grip should sensibly orient themselves to the full recorded image field, unless an open-matte distribution is explicitly ruled out.
