Overview
EN ISO 6428:1999 (ISO 6428:1982) - Technical drawings - Requirements for microcopying - specifies how original technical drawings and drawing-office documents should be executed so they can be reliably microcopied to high-quality microforms and yield legible enlargements. The standard expands on general drawing rules (ISO 128, ISO 3098, ISO 5457) to ensure consistent reproduction by microcopying and other reprographic systems. It is recommended for all drawing-office output intended for future archiving, imaging or reprographic interchange.
Key topics and technical requirements
- Document preparation: Originals must follow ISO 5457 sizes and layouts; drawings prepared for microcopying should favour matte, high-contrast surfaces to optimise legibility.
- Materials: Polyester drafting film (recommended minimum thickness 76 µm) offers superior dimensional stability, durability and reproducible quality compared with paper.
- Line quality and contrast: Lines and markings must be matt-finished with consistent density. A minimum contrast (optical density difference) is recommended to ensure legible microforms.
- Line thickness and spacing: Thicknesses are governed by ISO 128/ISO 3098; for A0/A1 originals a minimum line thickness is recommended to permit enlargement. Space between parallel lines should be at least twice the heaviest line thickness (minimum 0.7 mm).
- Lettering: Lettering should conform to ISO 3098/1. Minimum character heights and a minimum 2 mm spacing between characters/lines in lists and tables are required to ensure readability after microcopying.
- Areas and hatching: Avoid large solid black areas; use hatching or dotting to prevent loss of detail on microforms.
- Pencil work and erasure: Pencil drawings are discouraged; if used, choose polymer leads giving matt, even density and minimise handling. Erasure must avoid surface damage.
- Overlays, binding and handling: Consider effects of adhesive overlays (dust, ageing). Edge binding is not recommended unless unshrinkable tape is used.
- Storage and transport: Originals must not be folded. Rolling is permitted only for temporary transit (recommended tube diameter e.g. 75 mm) and documents should be stored flat or suspended.
Practical applications
- Creation of reliable archival microforms and reduced-size reproductions for engineering archives, land surveying, manufacturing, and construction.
- Standardising drawing-office output so documents remain reproducible by microfilm, microfiche, scanning and other reprographic systems.
- Improving long-term document preservation, transport efficiency and document-imaging workflows.
Who should use this standard
- Draftsmen, CAD and plotting operators
- Document imaging and reprographic service providers
- Archivists, records managers and engineering document controllers
- Quality and standards managers in engineering, manufacturing and construction organizations
Related standards
- ISO 128 - Technical drawings - General principles of presentation
- ISO 3098 - Technical drawings - Lettering
- ISO 5457 - Technical drawings - Sizes and layout of drawing sheets
- ISO 3272 - Microfilming of technical drawings and drawing-office documents
Keywords: EN ISO 6428:1999, ISO 6428, technical drawings, microcopying, microforms, reprographic, drawing office, polyester film, document imaging.
