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Filmmaking Dictionary: Number 4 / 4-Perf 35mm
Definition
4-perf 35mm is a motion-picture format that advances the film by four perforations for each frame. It is a traditional arrangement for vertically transported 35mm motion-picture film.
The four-perforation frame pitch does not specify one final aspect ratio. Camera aperture, soundtrack allowances in particular workflows, lens treatment and presentation crop determine the usable picture shape.
Image Area and Framing
A relatively tall frame can support different acquisition and finishing choices. Standard and Super 35 gate arrangements do not use exactly the same image area, so a generic ‘4-perf’ label is not a substitute for the camera’s actual framing specification.
An anamorphic workflow can use the frame with a squeezed image, while a spherical workflow can finish with an agreed crop. The viewing screen and post-production framing references must describe which area is intended for the audience.
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Film Consumption
At 24 fps, a nominal 400-foot roll of 4-perf 35mm lasts roughly four minutes and twenty-five seconds before practical handling allowances. Raising the frame rate consumes the roll more quickly.
Compared with 4-perf at the same speed, 3-perf uses 25% less film length and 2-perf uses 50% less. Those formats change frame spacing and available image height, so the choice involves more than a stock-budget calculation.
Practical Example
A production plans to record a tall negative area but release a wider image. The camera operator frames using the approved guides while the lab scans the required negative area. Editorial then uses the same active-picture reference. If the guide and finishing crop disagree, headroom and edge detail may change unexpectedly.
Preparation Checks
- Confirm the camera movement, gate and viewing screen.
- Identify standard or Super 35 framing as applicable.
- Specify spherical or anamorphic lens treatment.
- Agree on scan area and presentation crop.
- Calculate stock requirements using the shooting rate and reload allowances.
- Keep roll reports and laboratory instructions consistent with the setup.
Common Mistakes
Do not confuse four perforations per frame with a four-perforation-wide image or with the number of perforated edges. Likewise, the 35mm strip width does not establish the still-photography 36 × 24 mm image size used in a different film-travel arrangement.
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Frequently Asked Questions
Does 4-perf automatically mean Academy ratio?
No. It describes frame advance, while the gate and presentation determine the ratio.
Can 4-perf footage be finished digitally?
Yes. The scanned image can be edited, graded and delivered through a digital workflow.
Related Terms
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