Overview
SIST ISO 2240:2004 - Photography - Colour Reversal Camera Films - Determination of ISO Speed establishes the standardized method for measuring the ISO speed of colour reversal (slide) camera films. This standard is critical for ensuring uniform results when exposing films designed to produce continuous-tone pictorial images for viewing on transparency illuminators or for slide projection. The document applies to 8 mm and 16 mm motion-picture films used in non-professional settings, promoting consistency across consumer film products. Professional motion-picture films, regardless of their application, are not within the standard's scope.
The standard outlines specific procedures for exposure, processing, and densitometry to promote accurate determination of ISO speed, supporting photographers, laboratories, and manufacturers in achieving reliable film speed values.
Key Topics
- Scope of Application: Focuses on non-professional colour reversal camera films, including 8 mm and 16 mm motion-picture films, intended for projection or viewing on transparency illuminators.
- ISO Speed Determination: Describes the method of exposing and processing film samples to plot sensitometric curves, from which ISO speed values are calculated.
- Exposure and Processing Requirements: Specifies ambient conditions (temperature, humidity) and handling practices to ensure representative results that mirror typical user experiences.
- Densitometry Procedures: Details how to measure transmission density using densitometers conforming to ISO 5-2 and ISO 5-3 to ensure precise and repeatable outcomes.
- Product Marking and Labelling: Establishes guidelines for indicating ISO speed on film packaging, providing clear information to end-users.
Applications
- Film Manufacturers: Utilize the standard to assign accurate ISO speed ratings to colour reversal films, ensuring consumers can make informed choices for exposure settings.
- Photographers: Rely on ISO speed values derived from this method to achieve correct exposures, leading to optimal image quality for slides and projected images.
- Processing Laboratories: Follow standard procedures for testing and verifying film batches as part of quality control, guaranteeing consistency in film sensitivity.
- Camera Designers: Reference the standard to ensure that automatic and manual exposure controls are calibrated for films carrying an ISO speed determined by this method, supporting compatibility and ease of use for amateur users.
Related Standards
- ISO 5-2: Photography - Density measurements - Part 2: Geometric conditions for transmission density.
- ISO 5-3: Photography - Density measurements - Part 3: Spectral conditions.
- ISO 7589: Photography - Illuminants for sensitometry.
- ISO 2720: Photography - General purpose photographic exposure meters.
- ISO 2721: Photography - Cameras - Automatic exposure controls.
- ISO 2910: Cinematography - Projection screen luminance.
- ISO 3664: Viewing conditions - Graphic technology and photography.
- ISO Standards Handbook: Statistical methods for quality control.
Adhering to SIST ISO 2240:2004 ensures that colour reversal films are assigned ISO speeds with precision and consistency. This ultimately supports high-quality photographic results, facilitates standardization across global markets, and guarantees that amateurs and consumers can use films confidently for slide projection or transparency viewing. For those involved in film manufacture, camera design, or photography, understanding and applying this standardized method is essential for achieving reliable and reproducible photographic outcomes.
