Overview
ISO/TR 14672:2000 is an informative Technical Report from ISO TC 130 (Graphic technology) that documents the colour and spatial frequency statistics of the natural SCID (Standard Colour Image Data) images defined in ISO 12640. It provides a reference baseline of quantitative measures for the eight natural CMYK SCID images (N1–N8 and their alternate set N1A–N8A) to support objective and consistent evaluation of image processing, prepress workflows and device characterization.
Key topics
- Data sets and encoding
- Describes the primary (CEPS-style) and alternate (DTP/P1) CMYK encodings.
- Primary: assumed resolution 16 pixels/mm (2560 × 2048); tone 0% = data value 28, 100% = 228.
- Alternate: assumed resolution 12 pixels/mm (1920 × 1536); data range 0–255, derived by interpolation and remapping from primary.
- Colour distribution statistics
- Single-channel histograms for C, M, Y, K (figures and numeric tables).
- Average colour values per ink and interpretation guidance.
- 4×4 covariance matrices, principal axes and orthogonal matrices describing inter-channel correlations.
- Three-dimensional volumes (colour-gamut related metrics).
- Practical handling: textual inserts (ISO300/ISO400) are excluded from statistics; exclusion rectangles are defined and extended by 4 pixels to avoid edge effects.
- Spatial frequency characteristics
- Frequency-domain statistics that describe image detail and sharpness distribution (used to assess graininess and resolution effects).
- Supporting data
- Numerical tables and plots (tables 5–12 and 13–20, figures 5–12) included to serve as a reproducible statistical baseline.
Applications
- Prepress and colour management
- Baseline statistics for colour characterization, profiling and validating CMYK workflows.
- Image processing research and QA
- Compare original vs transformed images to quantify changes in colour balance, correlation and spatial detail.
- Device and process control
- Objective measures for output device testing, tone reproduction and sharpening/denoising evaluation.
- Standardized subjective testing
- Use the same SCID images with accompanying statistics to support repeatable subjective image-quality assessments.
Who should use it
- Colour scientists and imaging researchers
- Prepress and print production engineers
- Software developers of image-processing and colour-management tools
- Standards committees and laboratories performing comparative evaluations
Related standards
- ISO 12640:1997 - Graphic technology - Prepress digital data exchange - CMYK standard colour image data (defines the SCID images themselves)
- ISO 12639 - referenced for the P1 profile / DTP encoding used to create the alternate data set
Keywords: ISO/TR 14672, SCID, ISO 12640, CMYK standard colour image data, colour distribution statistics, spatial frequency, prepress, image processing, colour characterization.
