ISO 6428:1982

Overview

ISO 6428:1982 consolidates and expands the rules of ISO 128, ISO 3098 and ISO 5457 to define how original technical drawings and associated drawing-office documents should be executed for reliable microcopying. The standard's objective is practical: produce high-quality microforms that yield legible enlargements and that can also be reproduced by other reprographic systems.

Key benefits: improved archival microforms, predictable enlargement quality, and cross-reproducibility by different reprographic processes.

Key Topics

• Materials and sheets

  • Blanks or pre-printed sheets may be transparent, translucent or opaque, but the face used for drafting should be matt to reduce reflection and maximize contrast.
  • Polyester drafting film is recommended for dimensional stability and durability (document notes a minimum film thickness of about 76 μm).
  • Sheet sizes should comply with ISO 5457.
  • Edge binding is not recommended unless unshrinkable adhesive tape is used. Adhesive overlays require care due to dust accumulation and ageing.

• Lines, density and spacing

  • All lines (representations, symbols, lettering and revision marks) should have a matt finish and consistent density. A recommended minimum contrast value is 0.7 relative to the sheet background.
  • Parallel-line spacing should be at least twice the thickness of the heaviest line, with an absolute minimum spacing of 0.7 mm.
  • For AO and A1 originals that may be enlarged, a minimum line thickness of 0.35 mm is recommended.

• Lettering and text

  • Lettering shall comply with ISO 3098/1. Use of capital letters improves clarity for character images on microforms.
  • When mechanical lettering (typewriters, plotters) is used, matching the density of other lines is advised. Minimum character heights are recommended in the standard for different sheet sizes.

• Areas, pencil work and erasure

  • Avoid large solid black areas; use hatching or dotting if necessary.
  • Pencil drawings are not preferred but may be used if polymer leads and matt, even-density instruments are selected. Fixatives can reduce smudging but may affect future erasure.

• Storage and handling

  • Originals should be stored flat or suspended and not folded. Documents may be rolled for transit only, and then wrapped around a tube (typically large-diameter) and unwrapped promptly.

Applications

• Archival microfilming of technical drawings and associated office documents
• Preparing reproductions for engineering offices, libraries and record centers
• Establishing consistent reprographic quality across plotting, typewritten and hand-drawn originals

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 series - Microfilming procedures and quality criteria

Adopting ISO 6428:1982 practices ensures documents are future-proofed for microcopying and other reprographic workflows, improving legibility, reproducibility and long-term archival quality.