ISO 9957-3:1997

Overview

ISO 9957-3:1997, "Fluid draughting media - Part 3: Water‑based coloured draughting inks - Requirements and test conditions," defines requirements and test methods for water‑based coloured draughting inks intended for use in tubular technical pens on natural tracing paper (ISO 9961) and similar draughting media. The standard specifies classification, performance criteria and detailed test conditions to assess graphical, mechanical and ageing behaviour of coloured inks used for technical drawings.

Key topics and technical requirements

• Scope & Classification
  • Covers non‑black, low‑viscosity inks for coloured lines and filled areas.
  • Two types: Type A (relatively permanent - adhesion, fade and water resistance required) and Type B (less permanent, more fugitive).
• Test environment and equipment
  • Standard test atmosphere 23/50 (ISO 554).
  • Tubular technical pens per ISO 9175‑1 / ISO 9175‑2 and an electromechanical line‑draughting test machine (adjustable angle, load, speed, pitch).
  • Measurement tools: reflectance colorimeter (CIE Publication No. 15.2), microscope/profile projector (≥×20), filtered xenon lamp for fading tests.
• Performance tests and methods
  • Line width - microscopic or profile projection measurement; averaged over multiple points.
  • Colour - colour areas and CIE x,y coordinates defined in Annex A; colour measured under Standard Illuminant D.
  • Drying time - e.g., 150 mm line, smear test with gloved finger after 10 s (no smearing).
  • Adhesion - tape pull test and eraser test after 15 min drying (no visual loss of optical density for Type A).
  • Erasability / Redraughtability - erase a section and redraw; no feathering or ghosting permitted for Type A.
  • Resistance to water - water drop test after drying; no visual reduction in line intensity allowed for Type A.
  • Fade resistance - xenon lamp exposure and visual/CIELAB assessment against blue‑wool references (ISO 105‑B02, ISO 105‑J03).
• Shelf life and labelling
  • Ink properties must be preservable in original container for at least two years at supplier‑recommended storage conditions; manufacture date must be on the label.
• Designation and test report
  • Prescribed designation format (e.g., “Coloured ink ISO 9957‑3 – A”) and required test report elements.

Applications and users

• Ink manufacturers - product specification, quality control and labelling.
• Technical‑pen and draughting equipment producers - compatibility and performance verification.
• Testing laboratories - standardized methods for certification and comparative testing.
• Design and engineering drafters, archivists - guidance on permanence, reproduction behaviour and suitable inks for technical drawings.

Related standards

• ISO 9957‑1 (India ink), ISO 9957‑2 (non‑India ink)
• ISO 9175‑1 / 9175‑2 (tubular tips / performance)
• ISO 9961 (natural tracing paper)
• ISO 554 (standard atmospheres), ISO 105‑B02 / 105‑J03 (colour fastness and colour difference)
• CIE Publication No. 15.2 (Colorimetry)

Keywords: ISO 9957-3, water-based coloured draughting inks, technical pens, tracing paper, line width, drying time, adhesion, fade resistance, testing conditions.