Overview
ISO 2910:2018 - "Cinematography - Screen luminance and chrominance for the projection of film motion pictures" specifies required screen light levels and white-point chrominance for the theatrical (and applicable non‑theatrical) projection of 70 mm, 35 mm and 16 mm film at 24 frames per second. The standard defines how to measure screen luminance and chrominance, reference values, acceptable tolerances and recommended distributions to ensure consistent visual reproduction in cinemas, review rooms and presentation venues.
Key topics and technical requirements
- Scope and operating conditions
- Applies to 70 mm, 35 mm and 16 mm film projected at 24 fps; measurements taken with the projector running and no film in the gate.
- Reference luminance
- Screen centre reference luminance: 55 cd/m² for all formats.
- Recommended acceptable indoor range: 35–65 cd/m² (non‑theatrical lower limit may be 25 cd/m²).
- Luminance distribution and tolerances
- Edge luminance measured at 10% of screen width should be 50%–85% of centre (recommended 75%).
- Evenness should be symmetrical and checked from seating extremes, especially for high‑gain screens.
- Multiple-projector luminance match: same-format projectors ≤ 7 cd/m² difference; different-format sequential projectors ≤ 14 cd/m² difference.
- Chrominance (white point)
- Reference correlated colour temperature: 5800 K with an acceptable single-projector tolerance of ±400 K.
- Two-projector chrominance match should not differ by more than 400 K.
- Measurement instruments
- Luminance: photometer with acceptance angle ≤ 2° (recommended 1.5°), spectral sensitivity of the CIE Standard Observer.
- Chrominance: colour‑temperature meter or spot spectroradiometer with acceptance angle ≤ 2°.
- Measurement positions
- Primary measurement: ~1 m above floor on the theatre longitudinal axis at two‑thirds of the distance from screen to back row; additional checks at two positions one‑third of theatre width to each side.
- Stray light limits
- No visible stray source with luminance > 3.5 cd/m² from standard observing area.
- Stray light on screen: review rooms ≤ 0.4% of projector luminance; theatres ≤ 1.0%.
Applications and who uses it
- Cinema operators, projectionists and facilities managers - to set and verify projector output and screen performance for compliant theatrical presentation.
- Post‑production, mastering and QC teams - to validate reference viewing conditions in review rooms.
- Equipment manufacturers and calibrators - to design and certify projectors, photometers and spectroradiometers for film projection.
- Venue planners and acoustical/lighting consultants - to specify screening room lighting and stray‑light control.
Related standards
- CIE publications on colorimetry (referenced: CIE 15:2004) and other ISO/IEC color and measurement guidance.
- Developed by ISO/TC 36 (Cinematography); consult ISO 2910:2018 for full normative text and Annex A recommended distributions and tolerances.
Keywords: ISO 2910:2018, screen luminance, chrominance, 55 cd/m², 5800 K, theatrical projection, 35 mm, 70 mm, 16 mm, 24 fps, photometer, spectroradiometer.
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