Overview
ISO 2939:2015 specifies the position and dimensions of the picture image area and photographic sound records on 35 mm motion‑picture release prints. It covers optical projection prints (per ISO 2907) and television‑transmitted film (per ISO 1223), and defines the relative displacement of analogue and digital photographic sound records relative to the picture frame. The standard references ISO 17266 for multichannel analogue/digital sound and control‑record placements.
Key topics and technical requirements
- Picture image area position and dimensions: Defines the location and size of the projected picture on 35 mm release prints. Dimensions are given relative to un‑shrunk film and include tolerances for projection and transmission uses.
- Sound‑to‑picture displacement: The analogue sound record must precede its corresponding picture frame in the direction of film travel by 20 frames ± 0.5 frame (80 perforations ± 2 perforations). Analogue sound is the reference for setting correct displacement because its modulation is visible.
- Multichannel analogue and digital sound placement: Sound and control record positions and widths are specified via a normative reference to ISO 17266, ensuring consistent placement for multichannel systems and digital sound-control records.
- Technical characteristics: Requirements for image/sound separations and perforation areas - e.g., spaces between frames, image and sound records, and perforations should be substantially opaque to ensure proper reproduction.
- Operational notes (Annex A): Historical context on compensating for the speed of sound in air (previous editions suggested a 21‑frame displacement with a 1‑frame compensation for typical viewer distance); current practice and audience perception led to the standardized 20‑frame displacement.
Practical applications and users
ISO 2939:2015 is intended for professionals and organizations involved in the creation, duplication, distribution and exhibition of 35 mm release prints, including:
- Film laboratories and photochemical printing houses (frame and sound placement during printing)
- Post‑production and mastering facilities (sound‑to‑picture alignment)
- Theater projectionists and exhibitors (verification of film alignment and playback)
- Broadcast and telecine engineers (transmission of film content per ISO 1223)
- Equipment manufacturers (film gate, sound head and control‑record hardware)
- Archives and restoration specialists (maintaining historically accurate alignment)
Using ISO 2939 helps ensure consistent synchronization of picture and photographic sound across production, exhibition and broadcast workflows.
Related standards
- ISO 17266 - Multichannel analogue and digital photographic sound and control records
- ISO 2907 - Maximum projectable image area on 35 mm film
- ISO 1223 - Picture areas for television transmission
- ISO 4241, ISO 491, ISO 8567, ISO 2906 - complementary cinematography and print/specification standards
Keywords: ISO 2939:2015, 35 mm motion‑picture, picture image area, sound‑to‑picture displacement, analogue photographic sound, digital photographic sound, film projection standards.
Open preview (PDF)Cinematography — Picture image area on 35 mm motion-picture release prints — Position and dimensions and analogue and digital photographic sound to picture record displacement