Overview
ISO 11928-2:2000 - "Micrographics - Quality control of graphic COM recorders - Part 2: Quality criteria and control" defines methods to monitor and control the image quality of microforms produced by graphic COM recorders that output alphanumeric and graphic images onto black‑and‑white film. It is intended to be used with the test frames specified in ISO 11928-1 and supports initial qualification, routine quality checks and troubleshooting of COM‑generated microforms so they are comparable with conventional microfilm.
Key topics and technical requirements
- Test frames and usage: Procedures for applying the test frames from ISO 11928-1 to evaluate COM output, including which frames to record at start/end of test sequences.
- Evaluation and test runs: Guidance on running initial characterization tests, retaining reference samples, re‑running tests when deterioration is detected, and recording results for audit.
- System tolerances: Requirement to establish and document acceptable tolerances in agreement with equipment suppliers.
- Geometric checks: Measurements for frame size, linearity, orthogonality, line straightness, line width, image centering and positioning using a microscope with a measuring stage.
- Resolution and legibility: Methods to determine smallest resolvable line groups and the smallest legible characters (letter “e” groups) - resolution testing follows ISO 3334 procedures and uses microscope magnification ~1–3× effective reduction ratio.
- Density measurement: Use of densitometry in accordance with ISO 5‑2 and ISO 5‑3 to measure minimum and maximum diffuse densities; the standard provides acceptable density limits by film/process type.
- Special image checks: Tests for radial recording, curved‑line accuracy (distance from circumference to centre, constant spacing for double lines) and character display/rotation (distortion and character formation).
- Annex on line density: Informative guidance on correlating COM image line characteristics with duplicating/printing exposure and compatibility with source‑document microforms.
Practical applications
- Qualifying new graphic COM recorders before production use
- Routine quality control in micrographics labs, archives and reprographic services
- Troubleshooting image defects (geometric distortion, density, loss of resolution, character rotation)
- Ensuring COM‑generated drawings are comparable with conventional microfilm for storage, aperture‑card workflows and duplication
Who should use this standard
- Micrographics technicians and quality managers
- Document imaging specialists and archivists
- Manufacturers and service providers of graphic COM recorders
- Organizations producing CAD/technical drawing microforms and aperture‑card systems
Related standards
ISO 11928-2 is a practical, measurement‑based standard for anyone responsible for ensuring the fidelity and interoperability of COM‑generated microforms.