Overview
ISO 6342:2003 specifies a standardized method for measuring the thickness of the buildup area on aperture cards (camera and copy cards) used in micrographics. The method is intended for manufacturing and inspection purposes to ensure consistent physical characteristics of aperture cards used in microfilm and document-imaging systems.
Key topics and technical requirements
- Scope: Measurement method for the buildup area thickness on aperture cards.
- Apparatus: Use dead-weight dial micrometers (motor- or manually operated). The motor-operated micrometer is preferred.
- Pressure foot: circular, diameter 16 mm ± 0.5 mm; moves perpendicular to anvil.
- Loading: pressure foot shall exert 50 kPa ± 5 kPa (based on foot area).
- Lowering speed (motor): approximately 0.8 mm/s.
- Micrometer performance (values per ISO 534 equivalents):
- Indication error: 2.5 µm or 0.5%
- Error of parallelism: 5 µm or 1%
- Repeatability (standard deviation): 2.5 µm or 0.5%
- Conditioning and testing atmosphere:
- Samples loosely assembled and conditioned for at least 6 hours.
- Test conditions: 23 °C ± 1 °C and relative humidity 50% ± 2%.
- Measurement procedure:
- If manual micrometer: either lower to within 0.0075 mm then release, or lower at a controlled velocity between 0.8 mm/s and 12 mm/s.
- Maintain dead-weight loading for at least 2 s per measurement.
- Card thickness: at least four measurements away from card and buildup edges (≥ 6.35 mm); take the greatest value as card thickness.
- Buildup-area thickness: at least four measurements, one on each side of the buildup rectangle; centre pressure foot across the width; take the greatest value as buildup-area thickness.
- Buildup thickness = buildup-area thickness − card thickness.
- Centring guidance: Annex A provides clarifications for centring the pressure foot on different unitised microfilm-carrier constructions.
Applications and users
- Useful for aperture card manufacturers, micrographics equipment suppliers, and quality control/inspection laboratories.
- Relevant to archives, records management, and organizations using microfilm carriers where physical conformity and reliable card handling are important.
- Helps ensure consistent performance in document imaging, preservation, and automated handling systems.
Related standards
- ISO 534:1988 - Paper and board: determination of thickness (referenced for micrometer characteristics)
- ISO 6196-1:1993 - Micrographics vocabulary (general terms)
- ISO 6196-4:1998 - Micrographics vocabulary (materials and packaging)
Keywords: ISO 6342:2003, aperture cards, micrographics, buildup area thickness, micrometer measurement, card inspection, document imaging.
