January 2026: New ISO Standard Defines Water Resistance Testing for Optical Glass

In January 2026, the image technology sector saw the release of a critical new international standard—ISO 21575:2026—marking a significant advancement in the classification and testing of raw optical glass. This updated specification provides an improved, standardized approach to evaluating water resistance in optical materials through a powder test method. With optics underpinning a vast array of applications from high-precision cameras to medical equipment and advanced research instruments, the enhancements in ISO 21575:2026 are poised to impact manufacturers, laboratories, and quality management across the globe.

The article below unpacks the scope, technical requirements, and real-world implications of this singular standard update for January 2026, offering industry professionals valuable insights for compliance and operational excellence.

Overview

Image technology is at the core of modern innovation, driving progress in fields ranging from microscopy and photonics to consumer electronics and defense. At the heart of this field lies raw optical glass, whose properties directly determine the performance and reliability of sophisticated optical systems. Consistency in material quality and reliable resistance against environmental factors—like water exposure—are crucial.

International standards such as ISO 21575:2026 ensure that every batch of optical glass meets rigorous requirements, reducing risks in production and extending the lifespan of essential components. This article provides a detailed examination of the standard’s methods, classification schemes, and the benefits it brings to stakeholders in image technology.

Detailed Standards Coverage

ISO 21575:2026 — Water Resistance Testing for Raw Optical Glass

Raw optical glass — Powder test method for the water resistance of optical glass — Test method and classification

ISO 21575:2026, published in January 2026, specifies a precise powder test method for determining the water resistance of raw optical glass. Designed primarily for manufacturers, researchers, and quality control professionals in optical component production, the standard delivers a defined protocol for testing, classifying, and reporting water resistance properties.

Scope and Methodology

• Purpose: To standardize how the water resistance of raw optical glass is measured and classified, ensuring uniform interpretations and results.
• Applicability: This test method is intended for optical glass in its raw form, not finished components. It addresses the needs of both producers and end users who require assurance about glass suitability prior to further manufacturing or application.

Key Requirements and Specifications

• Test Procedure: The standard describes the powder method, where glass samples are ground to a specified particle size. These powders are subjected to water under controlled temperature and time conditions. The resultant leaching or degradation is measured using defined chemical and gravimetric analysis techniques.
• Classification: Results from the powder test are used to classify the glass into standardized grades based on water resistance. These classifications guide the selection of materials for various end uses.
• Reporting: ISO 21575:2026 prescribes what information must be included in test reports, ensuring traceability and reproducibility.

Notable Changes (from Previous Edition)

• Standard title revised for clarity.
• Updates throughout the document replacing the term “weight” with “mass.”
• Addition of sections 5.1 and 6.1, providing extended reagent and apparatus details.
• Inclusion of a new Figure 3 to support procedural understanding.
• Revision of test report requirements for greater transparency and QA alignment.
• Terminology refinement from “specific gravity” to “mass density,” and inclusion of calculation notes.

Who Needs to Comply

• Manufacturers of raw optical glass and preforms
• Precision lens and component manufacturers
• Organizations procuring optical materials for high-reliability applications
• Labs performing contract testing or QA audit functions

Practical Implications

• Adhering to ISO 21575:2026 enables reliable sourcing, process qualification, and risk reduction in finished optical products.
• Uniform classification empowers procurement and quality teams to set, evaluate, and compare material specifications globally.
• Enhanced technical guidance assists testing laboratories in aligning with the most recent international best practices.

Key highlights:

• Comprehensive, reproducible test protocol for water resistance assessment
• Standardized reporting requirements and enhanced traceability
• Revised terminology and updated technical sections improve clarity for practitioners

Access the full standard:View ISO 21575:2026 on iTeh Standards

Industry Impact & Compliance

The adoption of ISO 21575:2026 is about far more than laboratory procedure—it directly affects how businesses select raw materials, manage quality risk, and demonstrate compliance to clients and regulators. Implementing this standard:

• Ensures optical glass meets clearly defined international benchmarks, lowering the chance of premature component failure due to water-induced degradation.
• Offers procurement specialists and engineers greater confidence in sourcing, especially when supply chains are international.
• Enables organizations to respond efficiently to customer and regulatory audits by providing standardized, auditable test documentation.
• Compliance timelines typically fall in line with contractual updates, new product introductions, or as mandated by industry partners.
• Failing to adhere to the latest standard may result in procurement disputes, liability exposure, or compromises in optical device performance—risks especially critical in fields such as medical imaging, aerospace optics, and defense systems.

Technical Insights

ISO 21575:2026 builds on established testing science while offering important refinements for today’s manufacturers and laboratories:

• Sample Preparation: Emphasizes controlled, specified powder size for consistent interaction with water during testing.
• Process Control: Details on reagent types, apparatus calibration, and protocol adherence ensure high repeatability and comparability across different labs.
• Classification Scheme: Provides industry-accepted grading, allowing technical teams to quickly assess material suitability for a wide range of uses, from high-end camera lenses to laser optics.
• Reporting and Documentation: Expanded guidance on records, including the critical data points required for full traceability, supports best practices in quality assurance and regulatory filings.

Implementation Best Practices

1. Update Internal Procedures: Review and update internal test protocols to align with ISO 21575:2026, especially in terms of powder preparation and analysis.
2. Train Quality and Lab Personnel: Ensure all relevant staff are familiar with revised terminology, reporting formats, and procedural steps.
3. Audit Supply Chain: Communicate updated requirements to upstream suppliers and downstream partners to maintain alignment throughout the value chain.
4. Regular Equipment Calibration: Maintain apparatus and reagents to specifications for consistent, credible results.
5. Integrate Reporting: Embed new reporting guidelines into electronic laboratory notebooks and QMS platforms.

Conclusion & Next Steps

The January 2026 edition of ISO 21575 marks a new era for stakeholders in the image technology sector. Enhanced clarity in water resistance testing of raw optical glass helps organizations protect product integrity, streamline international operations, and uphold client trust. Professionals across manufacturing, quality, procurement, and research functions stand to benefit by rapidly adopting the revised standard.

Key takeaways:

• ISO 21575:2026 establishes a universally accepted baseline for the water resistance classification of optical glass, driving higher quality and reliability standards.
• Early adoption supports competitive differentiation and reduces quality-related non-conformance issues.
• Staying informed and compliant not only mitigates risk but also signals commitment to best practices in the global optics industry.

Next steps for organizations:

• Download and review the full ISO 21575:2026 standard
• Assess internal protocols for alignment
• Train teams and update supply contracts
• Monitor for further updates and related standards in image technology

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