ISO 8126:2019

Micrographics - Duplicating film, silver, diazo and vesicular - Specifications and measurement for visual density

This document specifies visual diffuse transmission densities for second generation silver-gelatin and diazo microforms and projection densities for second generation vesicular microforms. It also specifies methods of measurement. It does not apply to duplicates of microforms of technical drawings and other drawing office documents.

Micrographie — Films de duplication argentiques, diazoïques et vésiculaires — Spécifications et mesurage pour la densité visuelle

General Information

• Status: Published
• Publication Date: 09-Jan-2019
• ICS: 37.080 - Document imaging applications
• Technical Committee: ISO/TC 171 - Document management applications
• Drafting Committee: ISO/TC 171 - Document management applications
• Current Stage: 9093 - International Standard confirmed
• Start Date: 04-Jun-2024
• Completion Date: 13-Dec-2025

Relations

• Revises: ISO 8126:2000 - Micrographics - Duplicating film, silver, diazo and vesicular - Visual density - Specifications and measurement
• Effective Date: 23-Apr-2020

Overview

ISO 8126:2019 defines specifications and measurement methods for visual diffuse transmission density (silver‑gelatin and diazo) and projection density (vesicular) for second‑generation microform duplicates. The standard is aimed at ensuring legibility, reproducibility and quality control of duplicate microforms produced from masters. It does not apply to duplicates of technical drawings and drawing office documents.

Key measurement requirements include the use of densitometers conforming to ISO 5-2 and ISO 5-3 and specified sampling apertures. The standard also recommends use of test targets (for example a 6 % reflectance patch) when available to provide consistent reference measurements.

Key Topics

• Scope and purpose

  • Applies to second‑generation silver‑gelatin, diazo and vesicular duplicates.
  • Excludes duplicates of technical drawings and similar documents.

• Measurement methods

  • Silver‑gelatin and diazo duplicates: measure visual diffuse transmission density with a densitometer conforming to ISO 5-2 and ISO 5-3, sampling aperture 0.5 mm to 3.0 mm.
  • Vesicular duplicates: measure projection density using a densitometer for ISO standard projection density f/4.5 type, sampling aperture 0.5 mm to 3.0 mm.

• Measurement areas and sampling

  • Each measured area should be of even density and fully cover the sampling aperture.
  • When image density is non‑uniform, take multiple measurements across image areas, giving attention to the lowest density regions.
  • Prefer measuring on an image of a 6 % reflectance patch filmed on the original microform; otherwise measure between images with caution.

• Specified density ranges (selected values)

  • Silver‑gelatin, positive‑appearing duplicates: background visual diffuse transmission density 0.05 to 0.15.
  • Silver‑gelatin, negative‑appearing/direct positive: minimum or maximum limits specified relative to the inherent D of the duplicating film (e.g., direct positive distribution copies not greater than 0.18; direct positive intermediates not greater than 0.25).
  • Diazo duplicates: minimum density should be above the film's inherent D and not greater than 0.15; dark line films should have background density not less than 1.30.
  • Vesicular duplicates: projection density limits include positive background not greater than 0.25 and negative background minimums (e.g., not less than 1.20 or 1.80 for COM microforms as specified).

Applications

• Quality control in microfilm duplication facilities.
• Acceptance testing of distribution copies and intermediates.
• Routine verification of duplication processes to ensure legibility and archival reproducibility.
• Use when producing second‑generation duplicates for libraries, archives and document management workflows.

Related Standards

• ISO 5-1 / ISO 5-2 / ISO 5-3 - density measurement geometry and spectral conditions.
• ISO 6196 series - micrographics vocabulary and processing terms.
• ISO 6200 - density specifications and method for first‑generation silver‑gelatin microforms.

For implementation, refer to the normative references cited in ISO 8126:2019 and consult your national standards body for guidance on calibration, equipment selection and measurement procedures.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 8126
Third edition
2019-01
Micrographics — Duplicating
film, silver, diazo and vesicular —
Specifications and measurement for
visual density
Micrographie — Films de duplication argentiques, diazoïques et
vésiculaires — Spécifications et mesurage pour la densité visuelle
Reference number
©
ISO 2019
© ISO 2019
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ii © ISO 2019 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Measurement of density . 1
4.1 Method of measurement of silver-gelatin and diazo duplicates . 1
4.2 Method of measurement of vesicular duplicates . 2
4.3 Measurement areas . 2
4.3.1 Sampling aperture . 2
4.3.2 Use of density patches . . 2
5 Visual diffuse transmission density of duplicate microforms from source
documents and COM . 2
5.1 Silver-gelatin duplicates . 2
5.1.1 Positive-appearing duplicates . 2
5.1.2 Negative-appearing duplicates . 2
5.1.3 Direct positive duplicates . 3
5.2 Diazo duplicates . 3
6 Projection density of vesicular duplicates . 3
6.1 Vesicular duplicates of source document microforms . 3
6.1.1 Positive-appearing vesicular duplicates of source document microforms . 3
6.1.2 Negative-appearing vesicular duplicates of source document microforms . 3
6.2 Vesicular duplicates of COM microforms . 3
Foreword
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This document was prepared by Technical Committee ISO/TC 171, Document management applications.
This third edition cancels and replaces the second edition (ISO 8126:2000), of which it constitutes a
minor revision. In 5.2, “and for low contrast tonal diazo film, not greater than 0,90” has been removed
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iv © ISO 2019 – All rights reserved
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