Overview
ISO 9957-2:2019 - "Fluid draughting media - Part 2: Water-based non-India ink - Requirements and test conditions" specifies quality and test methods for water-based non-India inks used in draughting instruments on natural tracing paper (ISO 9961). The standard defines performance criteria and test conditions to deliver consistent black-line technical drawings while noting that non-India inks are generally less fade- and reproduction-resistant than India ink and are not recommended for archival originals.
Key topics and technical requirements
- Scope and purpose: Requirements for black water-based draughting fluids that do not use carbon black as primary colourant (dyes, dispersions, microfine pigments).
- Test atmosphere: Tests are carried out under standard test atmosphere 23/50 (ISO 554).
- Test specimens and equipment:
- Natural tracing paper conforming to ISO 9961.
- Electromechanical line-drawing device (adjustable angle, load, speed, pitch).
- Tubular technical pen, densitometer (ISO 5-2 / ISO 5-4), profile projector or measuring microscope, xenon lamp for fade testing.
- Measured properties:
- Line width - measured microscopically or by projection; averaged from multiple measurements and compared with allowable deviations (see standard).
- Optical density - transmission or reflection density measured with a densitometer; an optical density of around 1.0 is indicated as adequate contrast for many reproduction processes.
- Drying time - defined procedure (finger-glove smear test) to verify rapid set.
- Adhesion - tape test and eraser/lead abrasion tests to check durability of line intensity.
- Erasability / redraughtability - specified erase and redraw test; acceptable behaviour must be recorded in test report.
- Resistance to water - controlled water-drop test; limited spreading allowed but no loss of line intensity.
- Fade resistance - light fastness assessed with a filtered xenon lamp; non-India inks are explicitly not archival-grade.
- Shelf life: Graphical and mechanical qualities must be preservable for at least two years under supplier-recommended storage conditions.
Applications and users
ISO 9957-2:2019 is relevant for:
- Ink manufacturers developing water-based draughting inks and cartridges.
- Technical pen and instrument manufacturers specifying ink compatibility and performance.
- Quality control and testing laboratories conducting standardized performance tests.
- Drafting and CAD departments that still produce hard-copy technical drawings on tracing paper.
Note: Users needing archival permanence or guaranteed reproduction by traditional photomechanical methods should consider India inks or alternative archival processes.
Related standards
Keywords: ISO 9957-2:2019, water-based non-India ink, draughting inks, tracing paper, line width, optical density, drying time, adhesion, erasability, resistance to water, technical drawings.
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