Overview
ISO 3664:2009 - Graphic technology and photography - Viewing conditions - defines standardized viewing conditions for evaluating images on reflective and transmissive media (photographic and photomechanical prints, transparencies) and for images displayed in isolation on colour monitors. The standard aims to reduce color-appearance differences caused by inconsistent illumination, surround and display environments by prescribing reference illuminants, lighting tolerances and viewing procedures for color-critical appraisal and routine inspection.
Key topics and technical requirements
- Reference illuminant: Specifies CIE illuminant D50 as the reference spectral power distribution for visual appraisal and defines tolerances for chromaticity and ultraviolet content.
- Chromaticity & luminance: Requires control of illumination chromaticity (specified in the CIE 1976 UCS) and specific luminance/illuminance levels for different evaluation tasks.
- Two illumination levels: Defines a high level for critical comparison (e.g., proof vs. proof) and a lower level for practical appraisal and routine inspection to approximate typical viewing conditions.
- Viewing conditions (P1/T1/P2/T2): Distinguishes conditions for critical comparison (P1/T1), practical print appraisal (P2), and transparency viewing by projection (T2).
- Spectral quality & metamerism: Uses ISO/CIE 23603 and CIE 13.3-1995 methods to assess spectral conformity, colour-rendering index (CRI) and metamerism indices so that lamps correctly render colours and metamers under D50-like illumination.
- Monitor viewing: Specifies ambient surround and luminance recommendations for colour monitors when images are viewed without comparison to hardcopy (note: matching softcopy to hardcopy requires colour management and is outside the standard’s scope).
- Test methods: Includes measurement procedures for spectral power distributions, illuminance/luminance and projection resolution to verify compliance.
Practical applications and users
ISO 3664:2009 is used where visual color assessment must be consistent and repeatable:
- Photographers and photographic labs performing critical print appraisal and transparency comparison
- Graphic designers, proofing houses and print production teams managing colour matching between proofs and press sheets
- Quality control and inspection personnel in prepress and printing operations
- Museums, galleries and archivists assessing photographic and printed materials under standardized illumination
- Color management specialists selecting viewing booths, lightboxes and monitor setups
Benefits: minimizes miscommunication about colour, improves consistency in colour-critical workflows, and provides verifiable test methods for lighting equipment.
Related standards
- ISO/CIE 23603:2005 - Spectral quality of daylight simulators
- CIE 13.3-1995 - Colour rendering measurement
- ISO 13655 - Spectral measurement for graphic arts
- ISO 12646 - (Useful for monitor-to-hardcopy comparisons; complementary guidance)
Keywords: ISO 3664, viewing conditions, D50, colour reproduction, colour matching, illuminance, luminance, chromaticity, metamerism, colour rendering, prints, transparencies, color management.
