Overview
ISO 8687:1987 specifies standardized methods for measuring the signal-to-noise ratio (SNR) of variable-area photographic sound records on 8 mm Type S, 16 mm, and 35 mm motion-picture films. This standard from the International Organization for Standardization (ISO) details both a preferred and an alternative measurement method, ensuring consistent and reliable evaluation of the audio quality captured on film.
Accurate measurement of signal-to-noise ratio is essential for motion picture production and projection, as it directly influences the perceived clarity and fidelity of cinematic soundtracks. ISO 8687:1987 provides the film and cinema industry with a unified approach to test and compare the performance of photographic sound records, facilitating high-quality audio reproduction in professional environments.
Key Topics
Applications
ISO 8687:1987 is vital for industries and professionals involved in:
- Film Production Studios: Ensures consistency in assessing and comparing the audio track quality of various film formats.
- Post-Production Facilities: Enables verification of soundtrack integrity after editing or transfer of sound records.
- Motion Picture Archives: Assists in evaluating the condition and quality of archival film soundtracks.
- Film Equipment Manufacturers: Provides technical criteria for developing and calibrating sound recording and reproduction devices.
- Theaters and Projection Facilities: Supports accurate assessment and maintenance of playback equipment for optimal audience sound experiences.
By standardizing signal-to-noise measurement, stakeholders can reliably maintain or enhance sound quality in both analog and hybrid workflows, crucial for delivering high-fidelity cinematic audio.
Related Standards
For further context on the technical environment of ISO 8687:1987, the following related ISO standards and recommendations may be consulted:
- ISO 70 - Cinematography: Monophonic 35 mm negative photographic sound record - Position and dimensions.
- ISO 71 - Cinematography: 16 mm negative photographic sound record - Position and dimensions.
- ISO 2939 - Cinematography: Picture image area and photographic sound record on 35 mm motion-picture release prints.
- ISO 4243 - Cinematography: Picture image area and photographic sound record on 16 mm release prints.
- ISO 4244 - Cinematography: Photographic-monophonic sound test films - Specifications.
- CCIR Recommendation 468-2 - Measurement of audio-frequency noise in sound broadcasting and recording systems.
Together, these standards ensure a comprehensive framework for the specification, measurement, and assessment of motion-picture sound records, supporting quality assurance and interoperability across the cinematography sector.
Open preview (PDF)Cinematography — Signal-to-noise ratio of 8 mm Type S, 16 mm and 35 mm variable-area photographic sound records — Method of measurement
